<PAGE>   1


                                  UNITED STATES
                        SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM 10-Q

[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
          THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended September 30, 1999

                                       OR


[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
          THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from            to
                               -----------   ---------------
Commission file number  000-23213

                             YOUNG INNOVATIONS, INC.
             (Exact name of registrant as specified in its charter)


                   Missouri                                 43-1718931
(State or other jurisdiction of incorporation            (I.R.S. Employer
               or organization)                          Identification No.)


             13705 Shoreline Court East, Earth City, Missouri 63045
                    (Address of principal executive offices)
                                   (Zip Code)

                                 (314) 344-0010
              (Registrant's telephone number, including area code)


     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 (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

Yes   X    No
    -----     --------

Number of shares outstanding of the Registrant's Common Stock at October 31,
     1999: 6,504,296 shares of Common Stock, par value $.01 per share






                                       1
<PAGE>   2





                                     PART I
                              FINANCIAL INFORMATION

Item 1.   Financial Statements.

                             YOUNG INNOVATIONS, INC.
                           CONSOLIDATED BALANCE SHEETS
                        (IN THOUSANDS, EXCEPT SHARE DATA)

<TABLE>
<CAPTION>
                                                                            SEPTEMBER 30     DECEMBER 31
                                                                                1999            1998
                                                                           ------------     -----------
                                                                            (UNAUDITED)
<S>                                                                           <C>             <C>
                                     ASSETS
     CURRENT ASSETS:
       Cash and cash equivalents ..........................................   $    847        $  4,337
       Trade accounts  receivable,  net of allowance for doubtful accounts
        of $245 and $184,  respectively....................................      4,985           5,742
       Inventories ........................................................      4,177           3,030
       Other current assets ...............................................      2,191           1,677
                                                                              --------        --------
          Total current assets ............................................     12,200          14,786
                                                                              --------        --------
     PROPERTY, PLANT AND EQUIPMENT ........................................     12,460          11,713
                                                                              --------        --------
     OTHER ASSETS .........................................................      1,408             282
                                                                              --------        --------
     INTANGIBLE ASSETS ....................................................     32,058          27,963
                                                                              --------        --------
          Total assets ....................................................   $ 58,126        $ 54,744
                                                                              ========        ========

                      LIABILITIES AND STOCKHOLDERS' EQUITY
     CURRENT LIABILITIES:
       Current maturities of long-term debt ...............................   $    356        $     --
       Accounts payable and accrued liabilities ...........................      5,746           4,686
                                                                              --------        --------
          Total current liabilities .......................................      6,102           4,686
                                                                              --------        --------
     DEFERRED INCOME TAXES ................................................      1,857           1,857
                                                                              --------        --------
     LONG-TERM DEBT .......................................................        129              --
                                                                              --------        --------
     STOCKHOLDERS' EQUITY:
       Common stock, voting, $.01 par value, 25,000,000 shares
           authorized, 6,504,296 and 6,772,796 shares issued and
           outstanding in 1999 and 1998, respectively......................         65              68
       Additional paid-in capital .........................................     26,083          26,083
       Retained earnings ..................................................     27,412          22,359
       Common  stock in  treasury,  at cost,  308,414 and 39,914  shares in
        1999 and  1998, respectively.......................................     (3,522)           (309)
                                                                              --------        --------
          Total stockholders' equity ......................................     50,038          48,201
                                                                              --------        --------
          Total liabilities and stockholders' equity ......................   $ 58,126        $ 54,744
                                                                              ========        ========
</TABLE>



The accompanying notes are an integral part of these statements.










                                      2
<PAGE>   3


                             YOUNG INNOVATIONS, INC.
                        CONSOLIDATED STATEMENTS OF INCOME
                      (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                            THREE MONTHS ENDED  NINE MONTHS ENDED
                                                                               SEPTEMBER 30       SEPTEMBER 30
                                                                              1999      1998     1999      1998
                                                                             -------   ------   ------   --------
                   <S>                                                        <C>       <C>      <C>       <C>
                   NET SALES                                                 $10,762   $9,282   $30,388   $25,625
                   COST OF GOODS SOLD                                          4,763    4,306    13,424    11,400
                                                                             -------   ------   -------   -------
                                  Gross profit                                 5,999    4,976    16,964    14,225
                   SELLING, GENERAL AND ADMINISTRATIVE EXPENSES                3,037    2,589     8,761     7,479
                                                                             -------   ------   -------   -------
                                  Income from operations                       2,962    2,387     8,203     6,746
                                                                             -------   ------   -------   -------
                   OTHER INCOME (EXPENSE)
                          Other income (expense), net                             16       57        80       262
                                                                             -------   ------   -------   -------
                                  Income before provision for income taxes     2,978    2,444     8,283     7,008
                                                                             -------   ------   -------   -------
                   PROVISION FOR INCOME TAXES                                  1,161      941     3,230     2,695
                                                                             -------   ------   -------   -------
                                  Net income                                 $ 1,817   $1,503   $ 5,053   $ 4,313
                                                                             =======   ======   =======   =======

                                                                             -------   ------   -------   -------
                   BASIC EARNINGS PER SHARE                                  $  0.28   $ 0.22   $  0.77   $  0.64
                                                                             =======   ======   =======   =======

                                                                             -------   ------   -------   -------
                   DILUTED EARNINGS PER SHARE                                $  0.28   $ 0.22   $  0.77   $  0.63
                                                                             =======   ======   =======   =======

                   BASIC WEIGHTED AVERAGE SHARES OUTSTANDING                   6,504    6,773     6,586     6,759
                                                                             =======   ======   =======   =======

                   DILUTED WEIGHTED AVERAGE SHARES OUTSTANDING                 6,531    6,808     6,603     6,808
                                                                             =======   ======   =======   =======
</TABLE>



The accompanying notes are an integral part of these statements.



                                       3





<PAGE>   4







                             YOUNG INNOVATIONS, INC.
                      CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)
                                   (UNAUDITED)
<TABLE>
<CAPTION>
                                                                NINE MONTHS ENDED
                                                                   SEPTEMBER 30
                                                                 1999       1998
                                                                 ----       ----
<S>                                                            <C>        <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
  Net Income                                                   $ 5,053    $  4,313
                                                               -------    --------
      Adjustments to reconcile net income to cash flows from
        operating activities --
      Depreciation and amortization                              1,664       1,444
      Loss on sale of property, plant and equipment                 --         (23)
      Changes in assets and liabilities --
          Trade accounts receivable                              1,120        (650)
          Inventories                                             (251)       (464)
          Other current assets                                      80        (405)
          Other assets                                             (15)        630
          Accounts payable and accrued liabilities                (447)       (345)
                                                               -------    --------
               Total adjustments                                 2,151         187
                                                               -------    --------

               Net cash flows from operating activities          7,204       4,500
                                                               -------    --------

  CASH FLOWS FROM INVESTING ACTIVITIES:
     Acquisition of Panoramic, net of cash acquired                 --     (13,875)
     Acquisition of Athena Technology, net of cash acquired     (4,640)         --
     Investment in International Assembly, Inc.                 (1,050)         --
     Purchases of property, plant and equipment                 (1,381)       (920)
     Proceeds from sale of property, plant and equipment            --          14
     Proceeds from sale of marketable securities                    --         100
                                                               -------    --------
               Net cash flows from investing activities         (7,071)    (14,681)
                                                               -------    --------

  CASH FLOWS FROM FINANCING ACTIVITIES:
     Equity issuance costs                                          --         (47)
     Payments on long term debt                                   (406)         --
     Borrowings from revolving line of credit                    4,500          --
     Payments on revolving line of credit                       (4,500)         --
     Purchases of treasury stock                                (3,217)         --
                                                               -------    --------
             Net cash flows from financing activities           (3,623)        (47)
                                                               -------    --------

  NET DECREASE IN CASH AND CASH EQUIVALENTS                     (3,490)    (10,228)
  CASH AND CASH EQUIVALENTS, beginning of period                 4,337      12,761
                                                               -------    --------
  CASH AND CASH EQUIVALENTS, end of period                     $   847    $  2,533
                                                               =======   =========
</TABLE>

The accompanying notes are an integral part of these statements.




                                       4
<PAGE>   5



                             YOUNG INNOVATIONS, INC.
              NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS
                               SEPTEMBER 30, 1999
                    (DOLLARS IN THOUSANDS, EXCEPT SHARE DATA)

GENERAL:

     The interim financial statements are unaudited and reflect all adjustments
(consisting solely of normal recurring adjustments) that, in the opinion of
management, are necessary for a fair statement in the interim periods presented.
This report includes information in a condensed format and should be read in
conjunction with the audited consolidated financial statements and the footnotes
included in the Company's 1998 Annual Report on Form 10-K. The results of
operations for the three and nine months ended September 30, 1999 and 1998 are
not necessarily indicative of the results expected for the full year or any
other interim period.


1.   DESCRIPTION OF BUSINESS:

     Young Innovations, Inc. and its subsidiaries (the Company) develop,
manufacture and market supplies, and equipment used by dentists and dental
hygienists. The Company's product offering includes disposable and metal prophy
angles, cups, brushes, handpieces and related components, panoramic x-ray
machines and infection control products. The Company believes that it is the
leading manufacturer and marketer of prophy angles, cups, brushes, and panoramic
x-ray machines in the United States. The Company's manufacturing facilities are
located in Missouri, California, Indiana and Texas. Export sales were less than
10% of total net sales for 1998, 1997 and 1996 and for the nine months ended
September 30, 1999.

2.   SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

PRINCIPLES OF CONSOLIDATION

     The consolidated financial statements include the accounts of Young
Innovations, Inc. formed in July 1995 and its direct and indirect wholly owned
subsidiaries, Young Dental Manufacturing Company (Young Dental),  Denticator
International, Inc. (Denticator), Young Acquisitions Company and Panoramic
Rental Corp. (collectively, Panoramic), and Athena Technology, Inc. (Athena).
Panoramic is included since its acquisition on February 27, 1998. Athena is
included since its acquisition on April 2, 1999. The Company's portion of income
from its investment in International Assembly, Inc. (IAI) is included since the
investment May 18, 1999. All significant intercompany accounts and transactions
are eliminated in consolidation.

3.   ACQUISITIONS:

     On February 27, 1998, the Company acquired the assets and assumed certain
liabilities of Panoramic, an Indiana corporation. The Company paid $13,875 in
cash and issued $1,000 (62,500 shares) of common stock. The cash portion of the
purchase price was principally financed with the net proceeds remaining from the
Company's initial public offering. The acquisition was accounted for as a
purchase transaction. The purchase price was allocated based upon estimates of
fair value. The excess of purchase price over the estimated fair value of net
assets acquired (goodwill) was $10,445 and is being amortized over 40 years. The
results of operations for Panoramic are included in the consolidated financial
statements since February 27, 1998.



                                       5
<PAGE>   6


     On April 2, 1999, the Company acquired the net assets of Athena, a
California corporation. The Company paid $4,640 in cash and issued $430 of notes
payable. The cash portion of the purchase price was principally financed through
cash flows from operations and borrowings on the company's revolving line of
credit. The acquisition was accounted for as a purchase transaction. The
purchase price was allocated based upon estimates of fair value. The excess of
purchase price over the estimated fair value of net assets acquired (goodwill)
was $4,722 and is being amortized over 40 years. The results of operations for
Athena are included in the consolidated financial statements since April 2,
1999.


     The preliminary purchase price allocation is as follows:

       <TABLE>
       <S>                                                             <C>
       Trade accounts receivable..............................        $    363
       Inventories............................................             896
       Other current assets...................................              68
       Property, plant and equipment..........................             410
       Deferred tax asset.....................................             525
       Other assets...........................................              50
       Intangible assets......................................           4,727
       Current liabilities....................................          (1,507)
       Noncurrent liabilities.................................            (462)
                                                                      --------
       Total purchase price, cash ($4,640) and notes ($430)...        $ 5,070
       </TABLE>


     On May 18, 1999, the Company acquired a one third interest in IAI, a Texas
corporation. The Company paid approximately $1,050 in cash for its investment in
IAI. The acquisition was principally financed through cash flows from
operations. The investment is being accounted for under the equity method of
accounting. The Company's share of earnings for IAI is included before income
taxes. In connection with the IAI investment agreement, the Company has an
option to purchase the remaining two-thirds interest in IAI in early 2001.
Equity income is recorded net, after reduction of goodwill amortization based
on the excess of the amount paid for its interest in IAI over the fair value of
IAI's net assets at the date of the investment.

     The following unaudited pro forma information presents a summary of
consolidated results of operations of the Company as if these acquisitions had
occurred at the beginning of 1998, with pro forma adjustments to give effect to
amortization of goodwill and certain other adjustments, together with related
income tax effects. The unaudited pro forma information does not purport to be
indicative of the results of operations had these transactions been completed as
of the assumed dates or which may be obtained in the future.

     <TABLE>
     <CAPTION>
                                                                 NINE MONTHS      NINE MONTHS
                                                                    ENDED            ENDED
                                                                 SEPTEMBER 30,    SEPTEMBER 30,
                                                                     1999            1998
                                                                  (Unaudited)      (Unaudited)
     <S>                                                          <C>                <C>
     Net sales..............................................      $  31,431          $30,851
     Net Income.............................................          4,864            3,830
     Basic earnings per share...............................      $     .74          $   .57
     Diluted earnings per share.............................      $     .74          $   .56
     </TABLE>



                                       6
<PAGE>   7
4.   INVENTORIES:

     Inventories consist of the following:

     <TABLE>
     <CAPTION>
                                                                  SEPTEMBER 30 DECEMBER 31
                                                                      1999        1998
                                                                      ----        ----
     <S>                                                            <C>        <C>
     Finished products......................................        $1,373     $1,011
     Work in process........................................         1,657      1,069
     Raw materials and supplies.............................         1,147        950
                                                                    -------    -------
          Total inventories.................................        $4,177     $3,030
                                                                    =======    =======
     </TABLE>



5.   COMMON STOCK:

     In March 1999, the Company authorized the repurchase of up to 300,000
shares of its common stock. As of September 30, 1999, the Company had completed
the repurchase of 277,500 shares for $3,324. The Company reissued 9,000 shares
in conjunction with a stock option exercise for $107.



Item 2.   Management's Discussion and Analysis of Financial Condition and
Results of Operations

RESULTS OF OPERATIONS

THREE MONTHS ENDED SEPTEMBER 30, 1999 COMPARED TO THREE MONTHS ENDED
SEPTEMBER 30, 1998

NET SALES
     Net sales increased $1.5 million, or 15.9%, to $10.8 million in the third
quarter of 1999 from $9.3 million in the third quarter of 1998. The increase was
primarily a result of increased sales of prophy products and panoramic x-ray
machines and the inclusion of sales of Athena which was acquired April 2, 1999.

GROSS PROFIT
     Gross profit increased $1.0 million or 20.6%, to $6.0 million in the third
quarter of 1999 from $5.0 million in the third quarter of 1998. Gross profit
benefited from strong sales growth of existing products and from the acquisition
of Athena. Gross margin increased to 55.7% of net sales in 1999 from 53.6% in
1998. Gross margin was positively impacted by the consolidation of a majority of
the Denticator product line from California to Missouri and operating
efficiencies achieved in connection with the investment in IAI. Those
efficiencies were partially offset by the inclusion of Athena products, which
carry lower gross margins.

SELLING, GENERAL, AND ADMINISTRATIVE EXPENSES
     SG&A expenses increased $448,000, or 17.3%, to $3.0 million in the third
quarter of 1999 from $2.6 million in the third quarter of 1998. As a percent of
net sales, SG&A expenses increased to 28.2% in 1999 from 27.9% in 1998. The
increase in SG&A expenses is primarily attributable to the acquisition of
Athena.

INCOME FROM OPERATIONS
     Income from operations increased $575,000 or 24.1%, to $3.0 million in the
third quarter of 1999 from $2.4 million in the third quarter of 1998.

OTHER INCOME
     Other income decreased $41,000 to $16,000 in the third quarter of 1999 from
$57,000 in the third quarter of 1998. The decrease is primarily due to less
interest income in 1999 resulting from cash used in the acquisitions of Athena
and IAI.

PROVISION FOR INCOME TAXES
     Provision for income taxes increased $220,000 for the third quarter of 1999
to $1.2 million from $941,000 in the third quarter of 1998.





                                       7
<PAGE>   8



NINE MONTHS ENDED SEPTEMBER 30, 1999 COMPARED TO NINE MONTHS ENDED
SEPTEMBER 30, 1998

NET SALES

     Net sales increased $4.8 million, or 18.6%, to $30.4 million in 1999 from
$25.6 million in 1998. The increase was primarily a result of increased sales of
existing products and the inclusion of Panoramic sales for the full period in
1999 and of Athena sales from the acquisition April 2, 1999. Panoramic was
acquired February 27, 1998 and Athena was acquired April 2, 1999.

GROSS PROFIT
     Gross profit increased $2.7 million or 19.3%, to $17.0 million in 1999 from
$14.2 million in 1998. Gross profit benefited from increased sales of existing
products and from the acquisitions of Panoramic and Athena. Gross margin
increased slightly to 55.8% of net sales in 1999 from 55.5% of net sales in
1998. Gross margin was positively impacted by the consolidation of a majority of
the Denticator product line from California to Missouri and operating
efficiencies achieved in connection with the Investment in IAI.  These
efficiencies were partially offset by the inclusion of sales of Panoramic and
Athena products, which carry lower gross margins.

SELLING, GENERAL, AND ADMINISTRATIVE EXPENSES
     SG&A expenses increased $1.3 million, or 17.1%, to $8.8 million in 1999
from $7.5 million in 1998. The increase in SG&A expenses is primarily
attributable to the inclusion of Panoramic and Athena. As a percent of net
sales, SG&A expenses decreased to 28.8% in 1999 from 29.2% in 1998.

INCOME FROM OPERATIONS
     Income from operations increased $1.5 million or 21.6%, to $8.2 million in
1999 from $6.7 million in 1998.

OTHER INCOME
     Other income decreased $182,000 to $80,000 in 1999 from $262,000 in 1998.
The decrease is primarily due to less interest income in 1999 resulting from
cash used in the acquisitions of Athena and IAI.

PROVISION FOR INCOME TAXES
     Provision for income taxes increased $535,000 in 1999 to $3.2 million from
$2.7 million in 1998.

LIQUIDITY AND CAPITAL RESOURCES

     On February 27, 1998, the Company acquired the net assets of Panoramic. The
Company paid approximately $13.9 million in cash plus $1.0 million (62,500
shares) of its common stock. The acquisition was principally financed with cash
remaining from the net proceeds of the Company's initial public offering.

     On April 2, 1999, the Company acquired the net assets of Athena. The
Company paid approximately $4.64 million in cash and issued notes payable of
$430,000. The acquisition was principally financed through cash flows from
operations and borrowings on the Company's line of credit.

     On May 18, 1999, the Company acquired a one third interest in International
Assembly Inc. (IAI). The Company paid approximately $1.0 million in cash for its
investment in IAI. The acquisition was principally financed through cash flows
from operations.

     Historically, the Company has financed its operations primarily through
cash flow from operating activities and, to a lesser extent, through borrowings
under its credit facilities. Net cash flow from operating activities was $7.2
million for the nine months ended September 30, 1999 compared to $4.5 million
for the nine months ended September 30, 1998. Capital expenditures for property,
plant, and equipment were $1.4 million and $920,000 for the nine months ending
September 30, 1999 and 1998, respectively. Consistent with the Company's
historical capital expenditures, future capital expenditures are expected to
include injection molding equipment, panoramic X-ray machines for rental,
computer numeric controlled equipment and upgrades to production machinery and
to the Company's information systems. Management believes the Company has
adequate liquidity and capital resources to meet its needs on a short and
long-term basis.

                                       8
<PAGE>   9

YEAR 2000 COMPLIANCE

     With respect to the Company's information technology "IT" systems, the
mainframe operating system and the accompanying business critical applications
have been patched and letter certified as Year 2000 compliant by the Company's
hardware and software vendors. The personal computers ("PC's"), workstations,
servers and PC business applications have been patched and tested per the
vendors' instructions and are Year 2000 compliant. With respect to the non-IT
systems, the Company has obtained written certification of Year 2000 compliance
from its major administrative and manufacturing equipment vendors.

     There has not been a material adverse impact on the Company's operations or
financial condition as a result of IT and non-IT projects caused by the Year
2000 issue. The Company has annual maintenance contracts with most of its IT and
non-IT vendors, and external costs in the form of vendor software upgrades,
patches and testing programs were covered under these contracts. Current year
costs have been expensed as those costs have been incurred. The remaining
internal and external costs are not expected to materially exceed normal
operating expenses, and the Company has not deferred any significant capital
expenditures due to its Year 2000 efforts.


Item 3.   Quantitative and Qualitative Disclosures About Market Risk

Not applicable.


                                     PART II
                                OTHER INFORMATION


Item 6. Exhibits and Reports on Form 8-K

(a)  Exhibits.

     Number      Description


     27          Financial Data Schedule

(b)  Reports on Form 8-K.

     None

Signature

Pursuant to the requirements 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.

                                  YOUNG INNOVATIONS, INC.

November 12, 1999                  /s/ Arthur L. Herbst, Jr.
--------------------              ----------------------------------------
Date                              Arthur L. Herbst, Jr.
                                  Executive Vice President Strategic Planning &
                                  Chief Financial Officer





                                       9