SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, DC 20549
            ----------------------------------------------------

                                 FORM 10-K

(mark one)
[ X ] Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange
      Act of 1934 for the fiscal year ended January 2, 1999

[   ] Transition Report Pursuant to Section 13 or 15(d) of the
      Securities Exchange Act of 1934

                       Commission file number 1-12179

                       THERMO BIOANALYSIS CORPORATION
           (Exact name of Registrant as specified in its charter)

Delaware                                                         85-0429899
(State or other jurisdiction of        (I.R.S. Employer Identification No.)
incorporation or organization)

504 Airport Road
Santa Fe, New Mexico                                             87504-2108
(Address of principal executive offices)                         (Zip Code)

     Registrant's telephone number, including area code: (781) 622-1000

        Securities registered pursuant to Section 12(b) of the Act:

   Title of each class                 Name of exchange on which registered
 Common Stock, $.01 par value                American Stock Exchange

        Securities registered pursuant to Section 12(g) of the Act:
                                    None

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months, and (2) has been subject to the filing requirements for
at least the past 90 days. Yes [ X ] No [ ]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of the Registrant's knowledge, in definitive proxy or information
statements incorporated by reference into Part III of this Form 10-K or any
amendment to this Form 10-K. [ ]

The aggregate market value of the voting stock held by nonaffiliates of the
Registrant as of January 29, 1999, was approximately $49,286,000.

As of January 29, 1999, the Registrant had 17,547,416 shares of Common Stock
outstanding.

                    DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant's Annual Report to Shareholders for the year ended
January 2, 1999, are incorporated by reference into Parts I and II.

Portions of the Registrant's definitive Proxy Statement for the Annual Meeting
of Shareholders to be held on May 27, 1999, are incorporated by reference into
Part III.

<PAGE>


                                   PART I
                                   
Item 1.    Business

(a) General Development of Business

    Thermo BioAnalysis Corporation (the Company or the Registrant) operates in
three segments: Biomolecular Instruments and Consumables, Clinical Equipment and
Supplies, and Information Management Systems. The Company's Biomolecular
Instruments and Consumables segment designs, manufactures, and markets a broad
range of instruments, such as microplate handling and reading equipment, optical
biosensors, polymerase chain reaction (PCR) for deoxyribonucleic acid (DNA)
amplification, MALDI-TOF mass spectrometry, and capillary electrophoresis (CE).
The Company's Clinical Equipment and Supplies segment includes sample
preparation materials to highlight abnormal cells, blood gas and ion-selective
electrolyte (ISE) consumables, chemical reagents and accessories, and rapid
diagnostic tests for use in physician offices. The Company's Information
Management Systems segment manufactures systems which facilitate the monitoring
and analysis of samples as well as information storage and organization in
laboratories, industrial settings, and clinical testing sites.

    The Company's strategy is to develop and market a portfolio of instruments,
consumables, diagnostics, and information management systems for biochemistry,
healthcare, and other applications through the acquisition of complementary
businesses and technologies and through research and development of innovative
products. Since its incorporation in February 1995, the Company acquired the
Dynex Technologies division of Dynatech Corporation in February 1996, the
Affinity Sensors and LabSystems divisions of Fisons from Thermo Instrument
(effective March 29, 1996), and Labsystems Oy, Hybaid Limited, and Labsystems
Japan divisions of Life Sciences International PLC (LSI) from Thermo Instrument
(effective March 12, 1997). In May 1998, the Company acquired the Clinical
Products Group of LSI, comprised of Shandon Inc., and its related businesses,
including ALKO Diagnostics Corporation, from Thermo Instrument (effective March
12, 1997). Also in 1998, the Company acquired Data Medical Associates, Inc.
(DMA) in July; Trace Scientific Limited in August; BioStar, Inc. in November;
and Angewandte Gentechnologie Systeme GmbH (AGS) in December. Dynex supplies
automated systems, detection systems, and consumables to the immunoassay market.
Affinity Sensors supplies optical biosensors used in life sciences research by
the pharmaceutical and biotechnology industries, universities, and medical
research institutes. LabSystems designs, implements, and supports laboratory
information management systems (LIMS) and chromatography data systems (CDS) used
in research and development, quality assurance and control, and processing
plants. Labsystems Oy, based in Finland, manufactures microplate-based
immunoassay instruments and liquid-handling equipment. Hybaid, based in the
U.K., manufactures thermal cyclers and consumables for DNA amplification.
Labsystems Japan distributes products manufactured by Labsystems Oy, Hybaid, and
other LSI companies. Shandon is a leader in the manufacture of cytology and
histology equipment and consumables used to prepare microscope slides to
diagnose diseases, as well as equipment used in autopsies and forensics. ALKO
Diagnostics supplies consumables for blood gas and ISE analyzers, DMA and Trace
Scientific manufacture chemical reagents used in hospital and clinical
laboratories. BioStar manufactures rapid diagnostic tests used in the
physician's office to detect infectious diseases such as influenza, strep
throat, or mononucleosis. AGS, based in Germany, manufactures molecular biology
reagents for the life sciences market.

    As of July 5, 1998, the Company contributed the assets and liabilities of
its Eberline health physics division to a joint venture the Company formed with
Thermo Instrument Systems Inc. The joint venture was established to address the
nuclear instrumentation market. The Company received a 49% equity interest in
the joint venture, and initially receives 67% of the profit and losses of the
joint venture until the later of July 2000 or the achievement of certain
earnings targets by the joint venture. The Company's health physics division had
revenues of $13,371,000 in 1997. As a result of the formation of the joint
venture, the Company no longer consolidates the results of this business, but
instead records its share of the income as equity in earnings of unconsolidated
subsidiaries.

    The Company was incorporated in February 1995 as a wholly owned subsidiary
of Thermo Instrument. In September and October 1996, the Company conducted an
initial public offering of 1,670,000 shares of its common stock at $14.00 per
share for net proceeds of $20,782,000. In June 1998, the Company sold 4,000,000
shares of its common stock in a public offering at $18.125 per share for net
proceeds of $69,028,000. Of this amount, 1,000,000

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<PAGE>


shares were purchased by Thermo Electron Corporation. As of January 2, 1999,
Thermo Instrument owned 10,874,593 shares of the common stock of the Company,
representing 62% of such stock outstanding. During 1998*, Thermo Instrument
purchased 69,000 shares in the open market, for a total purchase price of
$729,000. Thermo Instrument develops, manufactures, markets, and services
instruments and software used for identification and quantification of complex
molecular compounds and elements in gases, liquids, and solids. Uses include
pharmaceutical research and clinical diagnostics, monitoring and measuring
environmental pollutants, industrial inspection, and test and control for
quality assurance and productivity improvement. In addition, Thermo Instrument
develops, manufactures, markets, and services equipment for the measurement,
preparation, storage, and automation of sample materials and photonics and
vacuum components for original equipment manufacturers (OEMs). Thermo Instrument
is a 85%-owned subsidiary of Thermo Electron. As of January 2, 1999, Thermo
Electron owned 3,815,837 shares of the common stock of the Company, representing
22% of such stock outstanding. During 1998, in addition to the 1,000,000 shares
purchased as part of the June 1998 public offering, Thermo Electron purchased
1,028,600 shares in the open market. The total amount paid by Thermo Electron
for all shares purchased in 1998 was $26,858,000. Thermo Electron is a world
leader in monitoring, analytical, and biomedical instrumentation; biomedical
products including heart-assist devices, respiratory-care equipment, and
mammography systems; and paper recycling and papermaking equipment. Thermo
Electron also develops alternative-energy systems and clean fuels, provides a
range of services including industrial outsourcing and environmental-liability
management, and conducts research and development in advanced imaging, laser,
and electronic information-management technologies.

Forward-looking Statements

    Forward-looking statements, within the meaning of Section 21E of the
Securities Exchange Act of 1934, are made throughout this Annual Report on Form
10-K. For this purpose, any statements contained herein that are not statements
of historical fact may be deemed to be forward-looking statements. Without
limiting the foregoing, the words "believes," "anticipates," "plans," "expects,"
"seeks," "estimates," and similar expressions are intended to identify
forward-looking statements. There are a number of important factors that could
cause the results of the Company to differ materially from those indicated by
such forward-looking statements, including those detailed under the heading
"Forward-looking Statements" in the Registrant's 1998 Annual Report to
Shareholders, which statements are incorporated herein by reference.

(b) Financial Information About Segments

    Financial information concerning the Company's segments is summarized in
Note 12 to Consolidated Financial Statements in the Registrant's 1998 Annual
Report to Shareholders, which information is incorporated herein by reference.

(c) Description of Business

    (i) Principal Products and Services

Biomolecular Instruments and Consumables

    The Company's proprietary immunoassay instruments and laboratory consumables
are offered through its DYNEX and Labsystems Oy businesses. The Company also
manufactures and markets a variety of proprietary products based on emerging
technologies, which include optical biosensor, PCR for DNA amplification, mass
spectrometry, and CE technologies. These products are offered through the
Company's Affinity Sensors, MALDI-TOF, Hybaid, and CE businesses.

--------------------
* References to 1998, 1997, and 1996 herein are for the fiscal years ended
  January 2, 1999, January 3, 1998, and December 28, 1996, respectively.

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    Immunoassay. The Company designs, manufactures, and supports products for
immunoassay testing. Immunoassays are studies performed for the qualitative and
quantitative analysis of the molecular interaction between biological and other
molecules. Immunoassay products are used in medical and pharmaceutical research;
clinical diagnostics including tests for pregnancy, hepatitis, and HIV;
veterinary medicine; agricultural diagnostics; water quality testing; and food
and beverage testing.

    In 1997, the Company introduced a combination luminescence and fluorescence
microplate, the Fluoroskan Ascent FL. The Fluoroskan offers on-board dispensers
for kinetic analysis, precise temperature control, orbital shaking, and robotic
integration capabilities. In 1998, the Company introduced the Multiskan Ascent,
an upgrade to the Company's optical photometer, and the Assist, an automated
system to load microplates into immunoassay dispensers and readers. The Company
also introduced microplates for tissue and cell cultures, as well as improved
microplates designed to eliminate "crosstalk" or interference between sample
wells.

    The Company has focused its sales efforts on the research and clinical
diagnostic markets, including chemical and pharmaceutical manufacturers,
healthcare and hospital facilities, universities, medical and pharmaceutical
research laboratories, veterinary and agricultural research laboratories, and
government institutions. The Company's products are used principally by large
clinical and research laboratories and manufacturers, including pharmaceutical
companies, where large-batch, high-volume testing methods are required.

    Laboratory Consumables. The Company designs, manufactures, and markets a
wide range of laboratory consumables. For example, the Company develops a
variety of hand-held, single and multi-channel pipettes, as well as tips which,
combined with pipettes, are used to transport and deposit precise amounts of
fluids and reagents during tests in clinical and research laboratories. The
Company's Labsystems Oy business produced the world's first continuously
adjustable micropipette and the first multi-channel pipette for microplates. The
Company's comprehensive range of Finnpipette liquid handling equipment includes
the Finnpipette Digital and the Finnpipette BioControl, and electronically
assisted trigger-action pipettes available in single channel and multi-channel
versions. The Company also manufactures disposable plastic pipette tips that are
designed to be used once and then discarded, as well as a variety of other
specialty, high precision plastic products, including microplates and
microstrips in which laboratory tests are carried out. In 1998, the Company
introduced a manual 16-channel pipette for use when laboratory testing does not
need automation.

    Optical Biosensors. Optical biosensor systems are a new technology used to
quantify biomolecules and characterize their functional properties. Unlike
competing technologies, which statically measure only the presence and quantity
of a biomolecule, optical biosensors dynamically measure the speed and strength
of the molecular interaction. The result is an analytical instrument that
provides previously unavailable information regarding molecular activity in real
time without the need for chemical or radioactive labels, thereby reducing the
time associated with the testing process. Researchers use the Company's optical
biosensors to assist them in understanding molecular interaction and how
molecules bind relative to one another.

    In 1997, the Company introduced a multi-analyte biosensor, IAsys Auto+
Advantage. The IAsys Auto+ offers improved sensitivity, and the availability of
prewritten scripts provides researchers with a high degree of flexibility when
designing experiments.

    MALDI-TOF Mass Spectrometry. Mass spectrometry measures the molecular weight
of a sample's components, thereby enabling identification and measurement of
organic chemical compounds, inorganic elements, or both, contained in the
sample. The Company offers an enhanced benchtop MALDI-TOF mass spectrometer that
has significantly enhanced resolution that was introduced in 1996.

    DNA Amplification. The Company designs, manufactures and markets PCR thermal
cyclers, which amplify - or duplicate - DNA. PCR is used by research
laboratories to diagnose and treat genetically based diseases, and in connection
with drug discovery efforts. The technology automates various research
procedures. The Company also manufactures hybridization ovens, which enable the
identification of a DNA sequence.

                                       4
<PAGE>

    New products in 1998 include the PCR Sprint, a high-throughput thermal
cycler, and the PCR Express Gradient System, a temperature-control system that
allows researchers to simultaneously test a collection of samples at various
temperatures, rather than at a single temperature, saving valuable research
time.

    Capillary Electrophoresis. CE is a purification and separation technique
commercially introduced in 1989. CE systems separate molecules as they move
through an extremely narrow tube, or capillary, that is charged with an electric
field. The largest market for CE systems and related supplies are pharmaceutical
companies. One of the principal applications for CE systems is the analysis and
separation of biomolecules such as proteins, peptides, and nucleic acids,
including DNA. Applications of DNA separation by CE include the identification
of specific individuals through DNA "fingerprinting" and the diagnosis of
diseases and specific genetic disorders such as leukemia, hepatitis, and sickle
cell anemia.

    The Company's line of CE systems includes a low-cost, manually controlled CE
system and a fully automated CE system with multiple wavelength detectors. In
1996, the Company introduced its new generation CE system that has more than
twice the sample capacity of competing products, thereby permitting users to
decrease labor costs by allowing longer periods of unattended operation. The
Company's CE systems offer high sensitivity, as well as advanced data handling,
control, and automation features. The Company also offers a line of CE
capillaries, buffers, and other consumables.

    The Company sells its immunoassay and optical biosensor products principally
through its direct sales force, OEMs, dealerships, and distributors throughout
the world. The Company maintains direct sales offices in several European
countries, Japan, and the United States. The Company also sells through
manufacturers' representatives.

    The Company distributes its laboratory consumables through regional and
national distributor sales channels in over 100 countries worldwide. The
Company's microplates are also sold to OEMs that then incorporate the
microplates into kits sold to diagnostic laboratories.

    The Company distributes its MALDI-TOF mass spectrometry products through its
direct sales force in the United States. The Company distributes its MALDI-TOF
mass spectrometry products in Japan through an arrangement with ThermoQuest
Corporation, a majority-owned subsidiary of Thermo Instrument. ThermoQuest also
distributes the Company's CE products and is the exclusive distributor of such
products in jurisdictions in which it maintains a direct sales force. The
Company also sells through dealers and distributors throughout the world.

Clinical Equipment and Supplies

    The Company addresses the clinical laboratory and healthcare markets with
equipment and supplies for the histology and cytology laboratories, chemical
reagents for clinical chemistry laboratories, and rapid diagnostic tests for use
in physician offices, health clinics, and hospitals. Equipment and consumables
for cytology, histology and pathology applications are manufactured through
Shandon Inc., and its related businesses. These businesses also supply
consumables for blood gas and ISE analyzers worldwide. Chemical reagents are
manufactured by Trace Scientific, DMA, and ALKO and rapid diagnostic test kits
are manufactured by BioStar.

    Cytology and Histology. The Company is a leader in the manufacture of
cytology and histology equipment used to prepare slides containing thin layers
of specially stained cells from patient samples, which enable medical
professionals to detect and diagnose diseases. Slide preparation is a multi-step
process, which, in most cases, requires a specimen to be stabilized, mounted,
sectioned, stained, and coverslipped. The Company offers a complete line of
equipment, accessories, and consumables to perform each step in the slide
preparation process. The Company's equipment is designed to enhance operator
safety by limiting contact with body fluid and tissue samples, as well as by

                                       5
<PAGE>

preventing fumes from reagents used in the slide preparation process from being
released into the laboratory. These products are used primarily by hospitals and
medical laboratories.

    The Company also manufactures and markets cytology and histology
consumables. The Company's Cytofunnels are patented disposable specimen
containers that are used in conjunction with its Cytospin. Other consumables
offered by the Company include biopsy bags, disposable cutting blades, knife
holders, reagents used by tissue processors, cell stains and fixatives, glass
slides, and slide racks. In addition, the Company manufactures and markets
immunohistochemistry kits, which are used to provide specific information about
a disease. For example, they are used to determine the primary location of a
malignancy based on the antibodies present in a secondary tumor specimen. New
products in 1998 include the Finesse Microtome (TM), an instrument that prepares
patient samples by slicing thin layers of sample for more accurate detection and
diagnosis, and introductions of more chemical reagents to broaden the product
line. The Company also introduced Netmon, a service to test the performance of
its Pathcenter tissue processors from a remote location in advance of a service
call, enabling service personnel to arrive equipped with the necessary
replacement parts to repair the instrument.

    Pathology Equipment. The Company is also a leading provider of vented
dissection equipment and refrigerated storage facilities used in autopsies and
forensic evaluations. The Company's products, which are sold under the
Shandon-Lipshaw brand name, are used by laboratories, morgues, medical schools,
medical examiners, and research and veterinary facilities worldwide. The Company
also designs, manufactures, and installs complete autopsy/mortuary facilities
based upon customers' specific space, function, and budget requirements.

    The Company manufactures and markets a series of stationary tables, ranging
from a standard autopsy table to an elevating, rotating autopsy table. These
tables are equipped with several safety features including a down draft
ventilation system to ensure that fumes are exhausted away from the work surface
and a built-in continuous table rinse to flush waste away from the table
surface. The Company's other principal pathology products include dissecting
sinks, cadaver lifts, transportable tables and carts, refrigerators, storage
facilities, and workstations. In addition to being used for autopsies, the
Company's workstations are used by medical laboratories for many types of gross
examinations and sectioning of specimens. In addition, the Company also markets
numerous pathology-related consumables including fume hoods and filters,
dissecting tools, instrument trays, and disposable boots and gloves.

    Blood Gas and ISE Consumables. The Clinical Products Group's ALKO Diagnostic
business supplies consumables for blood gas and ISE analyzers. Blood gas
analyzers are used to diagnosis the type and stage of certain diseases, such as
coronary artery disease, by measuring the levels of gases in blood samples. ISE
analyzers perform the same function by measuring the levels of electrolytes in
blood, plasma, serum, and urine samples. The Company's products are used to
calibrate, clean, and maintain these analyzers. The Company's products are
compatible with most major brands of blood gas and ISE analyzers, and are used
by hospitals and medical laboratories. The Company's principal products include
electrodes, buffers, calibrators, cartridges, and tubing.

    Chemical Reagents. The Company's clinical chemical reagents are developed as
a low-cost, high-quality alternative to OEM products, as well as to provide
advanced stabilization technology for, as an example, longer shelf life.

    Rapid Diagnostics. The Company manufactures rapid diagnostic tests for
infectious diseases based on a unique, patented thin-film optical immunoassay
technology. The Company provides test kits for influenza, strep throat, group B
strep, chlamydia, infectious mononucleosis, and pregnancy. New rapid diagnostic
products in 1998 include the Flu OIA(R), an optical immunoassay diagnostic test
kit cleared by the U.S. Food and Drug Administration (FDA) to detect influenza.
This test detects both influenza A and B in 15 minutes. The Company also
introduced new diagnostic test kits for pregnancy and infectious mononucleosis.

                                       6
<PAGE>

    The Company sells its cytology, histology, and pathology products to its
customers through its direct sales force in France, Germany, the United Kingdom,
and the United States, and through distributors.

    The Company's blood gas and ISE analyzers are sold through its direct sales
force in the United States, distributors and OEM arrangements.

    The Company's chemical reagants and rapid diagnostics are sold through its
direct sales force, distributors, and OEM arrangements.

Information Management Systems

    The Company offers laboratory information management systems and
chromatography data systems for use in laboratories, industrial settings, and
clinical testing facilities, through its LabSystems business. The Company's
information management systems are designed to facilitate the monitoring and
analysis of samples throughout the laboratory or clinical lifecycle, as well as
store and organize data.

    Laboratory Information Management Systems. The Company is recognized as one
of the world's leading LIMS suppliers. The Company also maintains an
implementation support group that provides software customization and project
management services for its customers. A substantial majority of the Company's
customers are Fortune 500 companies in the process chemical, aerospace,
pharmaceutical, environmental, oil and gas, petrochemical, automotive, food and
beverage, agricultural, and medical products industries. The Company's products
are used primarily for research and development, quality assurance and quality
control, and processing facilities.

    In 1998, the Company introduced Nautilus, a new PC-based LIMS product,
featuring a built-in instrument interface, which integrates laboratory
instruments into the LIMS. The integration is fully automated, eliminates
transcription errors, and allows data to be automatically imported from
instruments into the LIMS.

    Chromatography Data Systems. The Company's CDS products are open system
analytical tools that assist users in analyzing chromatographic data obtained
via gas and liquid chromatography and CE. In 1998, the Company introduced Atlas,
a CDS designed in joint development with chromatographers from some of the
Company's clients to ensure the new system met the needs of customers.

    The Company's LIMS and CDS products serve a variety of geographic markets.
The Company maintains direct sales and service offices in the United Kingdom and
the United States, as well as a network of distributors, in Australia, China,
Europe, and the United States.

    (ii) and (xi) New Products; Research and Development

    The Company's business includes the research and development of new
products. (See "Principal Products and Services.") The Company expended
$15,559,000, $14,057,000, and $7,298,000, respectively, on internally sponsored
research and development programs in 1998, 1997, and 1996,
respectively.

    (iii)   Raw Materials

    Raw materials, components, and supplies purchased by the Company are either
available from a number of different suppliers or from alternative sources that
could be developed without a material adverse effect on the Company. To date,
the Company has experienced no difficulties in obtaining these materials.

    (iv)    Patents, Licenses, and Trademarks

    The Company's policy is to protect its intellectual property rights and to
apply for patent protection when appropriate. The Company currently holds
several issued United States patents. The Company also has applications pending
for additional United States patents and a number of foreign counterparts for
its patents in various foreign

                                       7
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countries. In addition, the Company has registered, or other, trademarks. Patent
protection provides the Company with competitive advantages with respect to
certain systems. The Company believes, however, that technical know-how and
trade secrets are more important to its business than patent protection.

    The Company seeks to maintain the confidentiality of its proprietary
technology that is not covered by patent protection by requiring employees who
work with proprietary information to sign confidentiality agreements and by
limiting access by parties outside the Company to such confidential information.
There can be no assurance, however, that these measures will prevent the
unauthorized disclosure or use of this information, or that others will not be
able to independently develop such information. Moreover, as is the case with
the Company's patent rights, the enforcement by the Company of its trade secret
rights can be lengthy and costly, with no guarantee of success.

    (v)     Seasonal Influences

    Revenues from rapid diagnostics are higher during the winter months. In
addition, the Company's revenues across all segments generally are lower in the
third quarter of each calendar year, primarily because many of its European
operations and customers are on holiday during part of the summer months.

    (vi)    Working Capital Requirements

    There are no special inventory requirements or credit terms extended to
customers that would have a material adverse effect on the Company's working
capital.

    (vii)   Dependency on a Single Customer

    No single customer accounted for more than 10% of the Company's total
revenues in any of the past three years.

    (viii)  Backlog
<TABLE>
<CAPTION>
<S>                                                                                      <C>      <C>     

         The Company's backlog of firm orders at year-end 1998 and 1997 was:

(In thousands)                                                                              1998      1997
---------------------------------------------------------------------------------------- -------- ---------

Biomolecular Instruments and Consumables                                                 $ 9,820  $ 10,468
Clinical Equipment and Supplies                                                            8,497     6,055
Information Management Systems                                                            13,866    10,243
                                                                                         -------  --------

                                                                                         $32,183  $ 26,766
                                                                                         =======  ========


</TABLE>

    Certain of these orders are cancelable by the customer upon payment of a
cancellation charge. The Company anticipates that substantially all of the
backlog at January 2, 1999, will be shipped or completed during the next twelve
months. The Company does not believe the size of its backlog is necessarily
indicative of intermediate or long-term trends in its business.

    (ix)    Government Contracts

    Not applicable.


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    (x)     Competition

    The markets for the Company's products are highly competitive. In each of
the markets it serves, the Company competes with a number of companies, many of
which have greater engineering, manufacturing, and marketing resources than the
Company.

Biomolecular Instruments and Consumables

    Immunoassay. The Company competes in the immunoassay market primarily on the
basis of technological innovation, performance (including throughput and
sensitivity), flexibility, and price. In the detection-systems market, the
Company competes primarily with Bio-Tek Instruments, Inc. and Molecular Devices
Corporation. In the automated-systems market, the Company's main competitors
include Packard Biosciences, BioChem Pharma Inc., Immunosystems, Inc., Hamilton
Bonaduz AG, and Tecan AG.

    Laboratory Consumables. The Company competes in the laboratory consumables
market primarily on the basis of price, performance, and ease of use. The
Company's principal competitors in the consumables or plastics market include
Nalge Nunc Inc., Corning-Costar Corporation, Rainin Instruments, Greiner GmbH,
and Eppendorf GmbH.

    Optical Biosensors.  In the optical biosensors market, the Company
competes primarily on the basis of technological innovation, performance,
and price.  The Company's main competitor is Biacore International, Inc.

    MALDI-TOF Mass Spectrometry. The Company competes in the MALDI-TOF mass
spectrometry market primarily on the basis of the technical performance of its
MALDI-TOF mass spectrometers, as well as on the need in the analytical
biochemistry community for highly automated mass spectrometers. To a lesser
degree, the Company also competes on the basis of price. Principal competitors
in the mass spectrometry market include PerSeptive Biosystems, Inc., a
subsidiary of Perkin Elmer Corporation (Perkin Elmer); Shimadzu Corporation;
Bruker Instruments Inc.; and Micromass Ltd.

    DNA Amplification. The Company's thermal cyclers compete in the DNA
amplification market primarily on the basis of performance, ease of use, and, to
a lesser extent, price. Major competitors include Perkin Elmer and MJ Research
Technology.

    Capillary Electrophoresis.  The Company competes in the market for CE
systems primarily on the basis of technical performance and automation
features, and, to a lesser extent, price.  The Company's principal
competitors in the CE market include Beckman Instruments, Inc. (Beckman),
Bio-Rad Laboratories, Inc., and Hewlett-Packard.

Clinical Equipment and Supplies

    Cytology, Histology, and Pathology. The Company competes in the histology,
cytology, and pathology laboratory equipment and supplies market, primarily on
the basis of quality, price, and service. In the histology market, the Company's
main competitors include Leica Microsystems, Sakura, Carl Zeiss, Inc., and
Ventana Corporation. In the cytology market, the main competitors are Wescor
Inc. and Cytec Industries, and in the autopsy and forensic market, competitors
include Jewett, Mopec Inc., and Mortech.

    Blood Gas and ISE Consumables. The Company competes primarily on the basis
of price, customer relationships, and product quality in the blood gas and ISE
analyzers market. The Company's competitors include Chiron Corporation,
Radiometer, IL, AVL, Beckman Coulter, Inc., Dade-Behring, Inc., and NOVA.

    Chemical Reagents.  In the clinical chemistry reagent market, the
Company's competitors include Abbott Laboratories, BioChem Pharma, Chiron
Corporation, and Sigma.

                                       9
<PAGE>

    Rapid Diagnostics.  In diagnostic test kits, the Company's main
competitors are Abbott Laboratories, Becton, Dickinson and Company,
Roche-Boeringher Manheim, and Quindel Corporation.

Information Management Systems

    The Company competes in the high-end LIMS and CDS markets primarily on the
basis of the functionality, flexibility, and technical sophistication of its
systems, as well as on its ability to tailor its software packages to a
customer's specific laboratory protocols, its ability to provide superior
customer service and technical support, and price. Significant competitors in
the LIMS and CDS markets include Perkin Elmer, Beckman, Hewlett-Packard, the
Laboratory MicroSystems, Inc. subsidiary of Instron Corporation, and Waters
Instruments, Inc.

    (xii)   Environmental Protection Regulations

    The Company believes that compliance by the Company with federal, state, and
local environmental protection regulations will not have a material adverse
effect on its capital expenditures, earnings, or competitive position.

    (xiii)  Number of Employees

As of January 2, 1999, the Company employed 1,700 people.

(d) Financial Information About Geographic Areas

    Financial information about geographic areas is summarized in Note 12 to
Consolidated Financial Statements in the Registrant's 1998 Annual Report to
Shareholders, which information is incorporated herein by
reference.

(e) Executive Officers of the Registrant

     Name                 Age  Present Title (Fiscal Year First
                               Became Executive Officer)
     -----------------------------------------------------------------

     Colin Maddix          53  President and Chief Executive Officer (1998)
     Theo Melas-Kyriazi    39  Chief Financial Officer (1998)
     Paul F. Kelleher      56  Chief Accounting Officer (1995)

    Each executive officer serves until his successor is chosen or
appointed by the Board of Directors and qualified or until earlier
resignation, death, or removal.  Mr. Maddix has been Chief Executive
Officer, President, and a Director of the Company since March 1998.  Since
1992, Mr. Maddix has been President and Chief Executive Officer of the
Clinical Products Group of LSI, which includes Shandon Inc. and ALKO
Diagnostics Corporation.  Mr. Melas-Kyriazi was appointed Chief Financial
Officer of the Company and Thermo Electron on January 1, 1999.  He joined
Thermo Electron in 1986 as Assistant Treasurer, and became Treasurer in
1988.  In 1994, he was named President and Chief Executive Officer of
ThermoSpectra Corporation, a public subsidiary of Thermo Instrument.  In
1998, he became Vice President of Corporate Strategy for Thermo Electron.
Mr. Kelleher has held comparable positions for at least five years with
Thermo Instrument or Thermo Electron.  Messrs. Melas-Kyriazi and Kelleher
are full-time employees of Thermo Electron, but devote such time to the
affairs of the Company as the Company's needs reasonably require.

Item 2.     Properties

    The Company believes that its facilities are in good condition and are
adequate to meet its current needs and that other suitable space is readily
available if any leases are not extended. The Company also believes that none of
its manufacturing facilities are currently fully utilized and that the
additional manufacturing capacity available at such facilities will be
sufficient to satisfy its manufacturing requirements for at lease the next 12
months. With respect to

                                       10
<PAGE>

leases expiring in the near future, in the event that the Company does not renew
such leases, the Company believes that suitable alternative space is available
for lease on acceptable terms. The location and general character of the
Company's properties by industry segment as of January 2, 1999, are:

Biomolecular Instruments and Consumables

    The Company leases approximately 155,000 square feet of office, laboratory,
and production space in Finland under leases expiring through 2005;
approximately 64,000 square feet of office, manufacturing, engineering, and
laboratory space in Virginia, Massachusetts, and New Mexico, under leases
expiring through 2001; approximately 28,000 square feet of office and laboratory
space in Germany, under leases expiring through 2003; approximately 25,000
square feet of office, manufacturing, and laboratory space in England, under a
lease expiring in 2009; approximately 22,000 square feet of laboratory space in
Guernsey, under a lease expiring in 1999; approximately 22,000 square feet of
office space in Sweden, under a lease expiring in 1999; approximately 18,000
square feet of office, engineering, and laboratory space in the United Kingdom,
under leases expiring through 2002; approximately 55,000 square feet of office,
manufacturing, and warehouse space in Belgium, China, Japan, Russia, Spain,
France, and the Czech Republic under leases expiring through 2015.

Clinical Equipment and Supplies

    The Company owns approximately 95,000 square feet of manufacturing space in
Pennsylvania. The Company leases approximately 145,000 square feet of office,
manufacturing, laboratory, and distribution space in Texas, Colorado,
Massachusetts, and Florida, under leases expiring through 2003; approximately
76,000 square feet of manufacturing, office, and engineering space in the United
Kingdom, under leases expiring through 2014; approximately 45,000 square feet of
office, manufacturing, laboratory, and distribution space in Australia, under
leases expiring through 2002; approximately 19,000 square feet of office,
manufacturing, and distribution, space in Croatia under a lease expiring in
2000; and 22,000 square feet of office, manufacturing, laboratory, sales, and
distribution space in France, Germany, and New Zealand, under leases expiring
through 2004.

Information Management Systems

    The Company leases approximately 30,000 square feet of office space in the
United Kingdom, under a lease expiring in 2016; approximately 6,000 square feet
of office space in Massachusetts, under a lease expiring in 2001; approximately
4,000 square feet of office space in California, under a lease expiring in 1999;
approximately 14,000 square feet of office space in France, Germany, Spain,
Australia, Holland, Japan, and China, including 2,500 square feet subleased from
ThermoQuest and 2,500 square feet subleased from Thermo Optek, under leases
expiring through 2003.

Item 3.     Legal Proceedings

    Not applicable.

Item 4.     Submission of Matters to a Vote of Security Holders

    Not applicable.



                                       11
<PAGE>

                                  PART II
Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

    Information concerning the market and market price for the Registrant's
common stock, $.01 par value, and dividend policy is included under the sections
labeled "Common Stock Market Information" and "Dividend Policy" in the
Registrant's 1998 Annual Report to Shareholders and is incorporated herein by
reference.

Item 6.  Selected Financial Data

    The information required under this item is included under the sections
labeled "Selected Financial Information" and "Dividend Policy" in the
Registrant's 1998 Annual Report to Shareholders and is incorporated herein by
reference.

Item 7.  Management's Discussion and Analysis of Financial Condition and 
         Results of Operations

    The information required under this item is included under the caption
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's 1998 Annual Report to Shareholders and
is incorporated herein by reference.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

    The information required under this item is included under the caption
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's 1998 Annual Report to Shareholders and
is incorporated herein by reference.

Item 8.  Financial Statements and Supplementary Data

    The Registrant's Consolidated Financial Statements as of January 2, 1999,
and Supplementary Data are included in the Registrant's 1998 Annual Report to
Shareholders and are incorporated herein by reference.

Item 9.  Changes in and Disagreements with Accountants on Accounting and 
         Financial Disclosures

    Not applicable.


                                       12
<PAGE>

                                  PART III
Item 10. Directors and Executive Officers of the Registrant

    The information concerning directors required under this item is
incorporated herein by reference from the material contained under the caption
"Election of Directors" in the Registrant's definitive proxy statement to be
filed with the Securities and Exchange Commission pursuant to Regulation 14A,
not later than 120 days after the close of the fiscal year. The information
concerning delinquent filers pursuant to Item 405 of Regulation S-K is
incorporated herein by reference from the material contained under the heading
"Section 16(a) Beneficial Ownership Reporting Compliance" under the caption
"Stock Ownership" in the Registrant's definitive proxy statement to be filed
with the Securities and Exchange Commission pursuant to Regulation 14A, not
later than 120 days after the close of the fiscal year.

Item 11. Executive Compensation

    The information required under this item is incorporated herein by reference
from the material contained under the caption "Executive Compensation" in the
Registrant's definitive proxy statement to be filed with the Securities and
Exchange Commission pursuant to Regulation 14A, not later than 120 days after
the close of the fiscal year.

Item 12. Security Ownership of Certain Beneficial Owners and Management

    The information required under this item is incorporated herein by reference
from the material contained under the caption "Stock Ownership" in the
Registrant's definitive proxy statement to be filed with the Securities and
Exchange Commission pursuant to Regulation 14A, not later than 120 days after
the close of the fiscal year.

Item 13. Certain Relationships and Related Transactions

    The information required under this item is incorporated herein by reference
from the material contained under the caption "Relationship with Affiliates" in
the Registrant's definitive proxy statement to be filed with the Securities and
Exchange Commission pursuant to Regulation 14A, not later than 120 days after
the close of the fiscal year.

                                       13
<PAGE>

                                     
                                  PART IV
Item 14.   Exhibits, Financial Statement Schedules, and Reports on Form 8-K

(a,d) Financial Statements and Schedules

           (1) The consolidated financial statements set forth in the list below
               are filed as part of this Report.

           (2) The consolidated financial statement schedule set forth in the
               list below is filed as part of this Report.

           (3) Exhibits filed herewith or incorporated herein by reference are
               set forth in Item 14(c) below.

           List of Financial Statements and Schedules Referenced in this Item 14

           Information incorporated by reference from Exhibit 13 filed herewith:

              Consolidated Statement of Operations
              Consolidated Balance Sheet
              Consolidated Statement of Cash Flows
              Consolidated Statement of Comprehensive Income and
              Shareholders' Investment
              Notes to Consolidated Financial Statements
              Report of Independent Public Accountants

    Financial Statement Schedules filed herewith:

                Schedule II:  Valuation and Qualifying Accounts

    All other schedules are omitted because they are not applicable or not
    required, or because the required information is shown either in the
    financial statements or in the notes thereto.

(b) Reports on Form 8-K

    None.

(c) Exhibits

           See Exhibit Index on the page immediately preceding exhibits.


                                       14
<PAGE>

                                 SIGNATURES
    Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

Date:  March 19, 1999               THERMO BIOANALYSIS CORPORATION


                                    By: /s/ Colin Maddix
                                        Colin Maddix
                                        President and Chief Executive Officer

    Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
Registrant and in the capacities indicated, as of March 19, 1999.

Signature                           Title


By: /s/ Colin Maddix                President, Chief Executive Officer,
    Colin Maddix                     and Director


By: /s/ Theo Melas-Kyriazi          Chief Financial Officer
    Theo Melas-Kyriazi


By: /s/ Paul F. Kelleher            Chief Accounting Officer
    Paul F. Kelleher


By: /s/ Elias P. Gyftopoulos        Director
    Elias P. Gyftopoulos


By: /s/ Barry S. Howe               Director
    Barry S. Howe


By: /s/ Earl R. Lewis               Chairman of the Board and Director
    Earl R. Lewis


By: /s/ Jonathan W. Painter         Director
    Jonathan W. Painter


By: /s/ Arnold N. Weinberg          Director
    Arnold N. Weinberg

                                       15
<PAGE>

                  Report of Independent Public Accountants

To the Shareholders and Board of Directors of Thermo BioAnalysis
Corporation:

    We have audited, in accordance with generally accepted auditing standards,
the consolidated financial statements included in Thermo BioAnalysis
Corporation's Annual Report to Shareholders incorporated by reference in this
Form 10-K, and have issued our report thereon dated February 16, 1999, (except
with respect to the matterS discussed in Note 15, as to which the date is March
17, 1999). Our audits were made for the purpose of forming an opinion on those
statements taken as a whole. The schedule listed in Item 14 on page 14 is the
responsibility of the company's management and is presented for purposes of
complying with the Securities and Exchange Commission's rules and is not part of
the basic consolidated financial statements. The schedule has been subjected to
the auditing procedures applied in the audits of the basic consolidated
financial statements and, in our opinion, fairly states in all material respects
the consolidated financial data required to be set forth therein in relation to
the basic consolidated financial statements taken as a whole.



                                               Arthur Andersen LLP



Boston, Massachusetts
February 16, 1999

                                       16
<PAGE>
<TABLE>
<CAPTION>

   SCHEDULE II
                                      THERMO BIOANALYSIS CORPORATION
                                    Valuation and Qualifying Accounts
                                              (In thousands)
<S>                                 <C>         <C>         <C>         <C>         <C>         <C>    


Description                                      Provision    Accounts    Accounts   Other (a)     Balance
                                    Balance at  Charged to   Recovered     Written                  at End
                                     Beginning     Expense                     Off                 of Year
                                            of                                    
                                          Year
----------------------------------- ----------- ----------- ----------- ----------- ----------- -----------

Allowance for Doubtful Accounts

Year Ended January 2, 1999             $ 6,232     $   648     $    27     $(1,039)    $  (297)    $ 5,571

Year Ended January 3, 1998             $   991     $   606     $     -     $  (369)    $ 5,004     $ 6,232

Year Ended December 28, 1996           $   154     $   210     $     9     $  (188)    $   806     $   991

</TABLE>
<TABLE>
<CAPTION>
<S>                                 <C>           <C>            <C>           <C>           <C>    

Description                           Balance at    Established      Activity     Other (c)        Balance
                                       Beginning     as Cost of    Charged to                       at End
                                         of Year   Acquisitions       Reserve                      of Year
----------------------------------- ------------- -------------- ------------- ------------- --------------

Accrued Acquisition Expenses (b)

Year Ended January 2, 1999                $4,604        $ 2,435        $(2,219)      $(1,216)      $ 3,604

Year Ended January 3, 1998                $1,857        $ 7,677        $(3,665)      $(1,265)      $ 4,604

Year Ended December 28, 1996              $    -        $ 2,995        $(1,232)      $   94        $ 1,857


Description                           Balance at      Provision      Activity     Other (e)        Balance
                                       Beginning     Charged to    Charged to                       at End
                                         of Year    Expense (f)       Reserve                      of Year
----------------------------------- ------------- -------------- ------------- ------------- --------------

Restructuring Reserves (d)

Year Ended January 2, 1999                $    -       $  1,102        $ (913)       $   20       $    209

(a) Includes allowance of businesses acquired during the year as described in
    Note 2 to Consolidated Financial Statements in the Registrant's 1998 Annual
    Report to Shareholders and the effect of foreign currency translation.
(b) The nature of activity in this account is described in Note 2 to
    Consolidated Financial Statements in the Registrant's 1998 Annual Report to
    Shareholders.
(c) Represents reversal of accrued acquisition expenses and corresponding
    reduction in cost in excess of net assets of acquired companies resulting
    from finalization of restructuring plans and the effect of foreign currency
    translation.
(d) The nature of activity in this account is described in Note 10 to
    Consolidated Financial Statements in the Registrant's 1998 Annual Report to
    Shareholders.
(e) Represents the effect of foreign currency translation. (f) Excludes
    provision of $0.2 million for asset write-downs.
</TABLE>

                                       17
<PAGE>


                                 EXHIBIT INDEX
Exhibit
Number     Description of Exhibit

  2.1*     Purchase Agreement dated as of February 5, 1996, by and among the
           Company, Dynatech Corporation, and certain of their respective
           affiliates.

  2.2      Share Purchase Agreement dated as of May 6, 1997, between the Company
           and Thermo Instrument Systems Inc., with respect to Labsystems Oy and
           Hybaid Limited (incorporated by reference herein from Exhibit 2 to
           the Company's Quarterly Report on Form 10-Q for the quarter ended
           March 29, 1997 [File No. 1-12179]).
 
  2.3      Share Purchase Agreement dated as of July 30, 1997, between the 
           Company and Thermo Instrument Systems Inc., with respect to 
           Labsystems Japan  (incorporated  by  reference  herein from Exhibit 
           2 to the Company's  Quarterly  Report on Form 10-Q for the  quarter
           ended June 28, 1997 [File No. 1-12179]).

  2.4      Share Purchase Agreement dated as of May 11, 1998, between the 
           Company and Thermo Instrument Systems Inc. (incorporated by reference
           herein from Exhibit 2.4 to the Company's Registration Statement
           on Form S-1 [Reg. No. 333-52445]).

  2.5      Share Purchase Agreement dated as of May 11, 1998, between the
           Company and ThermoQuest Corporation (incorporated by reference herein
           from Exhibit 2.5 to the Company's Registration Statement on Form S-1
           [Reg. No. 333-52445]).

  3.1*     Certificate of Incorporation of the Registrant.

  3.2*     By-Laws of the Company.

  3.3      Certificate of Amendment of Certificate of Incorporation of the
           Registrant (incorporated by reference herein from Exhibit 3.1 to the
           Company's Quarterly Report on Form 10-Q for the quarter ended October
           3, 1998 [File No. 1-12179]).

  4*       Form of Common Stock Certificate.

 10.1*     Corporate Services Agreement dated as of February 27, 1995, between
           Thermo Electron and the Company.

 10.2      Thermo Electron Corporate Charter, as amended and restated effective
           January 3, 1993 (incorporated by reference herein from Exhibit 10.1
           to Thermo Electron's Annual Report on Form 10-K for the fiscal year
           ended January 2, 1993 [File No. 1-8002]).

 10.3*     Tax Allocation Agreement dated as of February 27, 1995, between
           Thermo Electron and the Company.

 10.4      Amended and Restated Master Repurchase Agreement dated as of December
           28, 1996, between Thermo Electron and the Company (incorporated by
           reference herein from Exhibit 10.4 to the Company's Annual Report on
           Form 10-K for the fiscal year ended December 28, 1996 [File No.
           1-12179]).

                                       18
<PAGE>

                               EXHIBIT INDEX
                                     
Exhibit
Number     Description of Exhibit

 10.5      Amended and Restated Master Guarantee Reimbursement and Loan
           Agreement dated as of December 2, 1997, between Thermo Electron and
           the Company (incorporated by reference herein from Exhibit 10.39 to
           Thermo Instrument's Annual Report on Form 10-K for the fiscal year
           ended January 3, 1998 [File No. 1-9786]).

 10.6      Amended and Restated Master Guarantee Reimbursement and Loan
           Agreement dated as of December 2, 1997, between Thermo Instrument and
           the Company (incorporated by reference herein from Exhibit 10.6 to
           the Company's Annual Report on Form 10-K for the fiscal year ended
           January 3, 1998 [File No. 1-12179]).

 10.7*     Equity Incentive Plan of the Company.

           In addition to the stock-based compensation plans of the Company, the
           executive officers of the Company may be granted awards under
           stock-based compensation plans of Thermo Electron and Thermo
           Instrument for services rendered to the Company or such affiliated
           corporations. The terms of such plans are substantially the same as
           those of the Company's Equity Incentive Plan.

 10.8*     Deferred Compensation Plan for Directors of the Company.

 10.9*     Directors' Stock Option Plan of the Company.

 10.10*    Form of Indemnification Agreement for Officers and Directors.

 10.11*    Asset Transfer Agreement dated as of February 27, 1995, between
           Thermo Instrument and the Company.

 10.12*    Asset Transfer Agreement dated as of February 27, 1995, between
           Thermo Separation Products Inc. and the Company.

 10.13*    Exclusive License Agreement dated as of February 27, 1995,
           between Thermo Separation Products Inc. and the Company.

 10.14*    Exclusive License Agreement dated as of February 27, 1995, between
           the Company and Thermo Separation Products Inc.

 10.15*    Manufacturing Agreement dated as of February 27, 1995, between Thermo
           Separation Products Inc. and the Company.

 10.16*    Note Purchase Agreement dated as of July 22, 1996, between Thermo
           Instrument and the Company.

 10.17*    $50,000,000 Principal Amount 4.875% Convertible Subordinated Note due
           2001 dated July 22, 1996.

 10.18*    Asset and Share Purchase Agreement dated as of July 22, 1996, among
           SID Instruments Inc., HB Instruments Inc., the Company, and Thermo
           Instrument.

 10.19*    Asset Purchase Agreement dated as of July 22, 1996, among Thermo
           LabSystems Limited, FI Instruments Inc., Thermo FAST U.K. Limited,
           the Company, and Thermo Instrument.

                                       19
<PAGE>

                               EXHIBIT INDEX
                                     
Exhibit
Number     Description of Exhibit

 10.22     Restated Stock Holding Assistance Plan and Form of Promissory Note
           (incorporated by reference herein from Exhibit 10.20 to the Company's
           Annual Report on Form 10-K for the fiscal year ended December 28,
           1996 [File No. 1-12179]).

 10.21     $50,000,000 Principal Amount Promissory Note, due 1999, dated April
           30, 1998 (incorporated by reference herein from Exhibit 10.21 to the
           Company's Registration Statement on Form S-1 [Reg.
           No. 333-52445]).

 13        Annual Report to Shareholders for the year ended January 2, 1999
           (only those portions incorporated herein by reference).

 21        Subsidiaries of the Registrant.

 23        Consent of Arthur Andersen LLP.

 27        Financial Data Schedule.


Each exhibit above which is marked with an asterisk (*) is incorporated by
reference to the correspondingly numbered exhibit to the Company's Registration
Statement on Form S-1 [File No. 333-8697].