Document:

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                                                                    Exhibit 4.12

                              EMPLOYMENT AGREEMENT

                                 by and between

                                     QIAGEN,
                           Auf dem Wolf 39, 4052 Basel

                             - hereinafter QIAGEN -

                                       and

                               Mr. Peer M. Schatz

                            - hereinafter Employee -

1.   Introduction

     Mr. Schatz is the Financial Controller of QIAGEN GmbH in Dusseldorf. Mr.
     Schatz is Director and Financial Controller of QIAGEN AG in Basel as well.
     The following employment agreement relates exclusively to this activity.

2.   Position and Function

     Mr. Schatz is directly responsible to and reports to the Board of
     Directors. His main tasks are administration and finance.

3.   Commencement, Duration and Conclusion of Employment Relationship

3.1  Commencement

     Mr. Schatz has been employed by QIAGEN AG since September 15, 1994.

     3.2. Duration and Conclusion

     The employment agreement is concluded for an indeterminate time period. The
     employment agreement may be terminated at the end of any calendar month,

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     with three months notice communicated by registered letter. The Company
     reserves the right to terminate Employee at any time if serious cause
     exists.

4.   Obligations of Mr. Schatz

     4.1 Fiduciary and Secrecy Obligations

     Mr. Schatz is obligated to perform all tasks in conjunction with the
     aforementioned activities conscientiously and to be best of his abilities,
     to safeguard DIAGEN's interests in every respect, and to maintain secrecy
     on all confidential matters and activities. This secrecy obligation extends
     in full measure wherever may be applicable to the time subsequent to
     commencing employment.

     4.2 Work Time

     Mr. Schatz' schedule shall be determined by the scope and urgency of
     contingent activities, on average requiring one day per week.

     5.  QIAGEN AG Obligations

     5.1 Salary

         The Employee shall receive a gross monthly salary of FR 5,000.--(in
         words five thousand francs). The Employee is not entitled to receive a
         thirteenth salary. The gross salary includes all legally required
         insurance contributions such as AHV, ALV, IV, EO and deductible
         withholding tax. Since Mr. Schatz shall perform his activities in
         Germany and is sufficiently insured by BVG against all risks, he has no
         additional obligation under BVG regulations.

     5.2 Dependents Allowance

         Mr. Schatz' entitlement to claim a Dependents Allowance is expressly
         regulated in his agreement with QIAGEN GmbH. According to the
         aforementioned agreement, he shall not be entitled to receive a
         Dependents Allowance.

     5.3 Payment of Salary During Illness or Accident and Fulfillment of Legal
         Obligations

         The scope of salary payment during illness, accident and fulfillment of
         legal obligations is also determined by the regulations governing the
         forementioned

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          employment relationship contained within the agreement between QIAGEN
          GmbH and Mr. Schatz.

     5.4  Expenses

          Necessary expenditures and expenses in the interests of the firm as
          well as compensation for the use of private auto for business purposes
          shall be reimbursed according to the provisions relating to
          compensation of expenses.

     6.   Final Provisions

     6.1. Amendments and Supplements

          Any future amendments of and/or supplements to the agreement shall be
          in writing in order to acquire legal effect. For questions which have
          not been addressed by either the present agreement or that between Mr.
          Schatz and QIAGEN GmbH, the provisions of Swiss Code of Obligations
          (OR).

     6.2  Disputes

          In the case that disputes arise in conjunction with this agreement,
          the contractual partners shall attempt to remedy these in an amicable
          fashion. If this is not possible, the applicable court of jurisdiction
          shall be the city of Basel.

     6.3  Integrated Component of Employment Agreement

          Provisions on compensation of expenses and holidays form an integral
          component of this employment agreement.

     Basel, May 29, 1998                               QIAGEN A.G.

      /s/ Peer M. Schatz                               /s/ Vincent Sigrist
     -------------------                               ----------------------
     Peer M. Schatz                                    General Manager

     ___________________________                       /s/ Sabine Buhrer
                                                       ----------------------
                                                       Finance & Administration
                                                       Manager<PAGE>

                                                                    Exhibit 4.13

EMPLOYMENT AGREEMENT

THE UNDERSIGNED:

1.  The public limited liability company QIAGEN N.V., having its registered
    office at Spoorstraat 42 - 52, NL - Venlo, in this matter duly represented
    by Mr. Peer Schatz, hereinafter to be referred to as the `Company';

and

2.  METIN COLPAN, hereinafter to be referred to as the `Managing Director';

WHEREAS

..   by the establishment of the Company in 1996 the Managing Director has been
    appointed as the Statutory Managing Director of the Company;

..   the Company and the Managing Director hereby confirm the employment
    conditions of the Managing Director as follows:

Article 1: Rights and obligations

1.  As the Statutory Managing Director of the Company, the Managing Director
    has all rights and obligations as laid down in the law, in the articles of
    association of the Company and in any and all instructions that are or may
    be adopted by the Company.

2.  The Managing Director shall undertake every effort in order to further the
    interests of the Company.

3.  The Managing Director shall refrain from accepting compensation or payment
    for activities or occupations other than pursuant to this agreement without
    the prior consent of the shareholders' meeting of the Company.

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Article 2: Duties

1.  The Managing Director will hold the position of Chief Executive Officer
    for the Company.

2.  Without the Company's prior written consent, the Managing Director will not
    perform any other work for pay during his employment term, nor will he,
    alone or with other persons, directly or indirectly, establish or conduct
    a business that is competitive with the Company's business, whatever its
    form, or take any financial interest in or perform work gratuitously or for
    remuneration for such a business.

Article 3: Commencement, term and notice

The employment contract is in force since January 1, 1998 for an indefinite
period of time. The employment may be terminated by either party with due
observance of the statutory notice period. Notice may be given only in writing.

Article 4: Salary

The Managing Director will receive a gross annual salary of DM 50.400 including
an annual holiday allowance of 8% of the gross basic annual salary.

Article 5: Expense Allowance

The Company will compensate the Managing Director for expenses directly related
to the performance of his work, but only insofar as that compensation may be
provided tax free and premium free.

Article 6: Holidays

The Managing Director is entitled to take holidays whenever that is possible
under his business responsibilities.

Article 7: Insuranes

The Company will not take out any insurances for the Managing Director other
than customary or required for business activities carried out by QIAGEN N.V.

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Article 8: Non-competition Clause

1.  For a period of 1 year after the termination of the employment contract,
    the Managing Director may not, without the Company's prior written consent,
    engage in any activities that in any way whatsoever directly or indirectly
    compete with the Company in the nucleic acid handling separation and/or
    purification industry or a company affiliated with it, and the Managing
    Director may not establish, conduct (alone or with others) or cause the
    conduct of any competing business or take any interest in or be employed in
    any way whatsoever by such business, whether or not for consideration.

2.  If the Managing Director violates the non-competition clause contained in
    this Article, he will forfeit to the Company a penalty of NLG100,000 for
    each breach, payable on demand, as well as a penalty of NLG 10,000 for
    each day that the breach continues, without prejudice to the Company's
    right to claim full damages instead.

3.  Upon each breach of the non-competition clause contained in this Article,
    the period referred to in paragraph 1 will be extended by the duration of
    that breach.

Article 9: Confidentiality

Neither during the term of the employment contract nor upon termination thereof
may the Managing Director inform any third party in any form, directly or
indirectly, of any particulars concerning or related to the business conducted
by the Company or its affiliated companies, which the Managing Director could
reasonably have known were not intended for third parties, regardless of whether
such information includes any reference to its confidential nature or ownership
and regardless of how the Managing Director learned of the particulars.

Article 10: Return of Property

Upon termination of the employment contract, the Managing Director will be
obliged to immediately return to the Company all property belonging to the
Company, including materials, documents and information copied in any form
whatsoever, articles, and keys.

Article 11: Applicable Law

This employment contract and the appendices/schedules will be governed by the
laws of the Netherlands.

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Drawn up in duplicate originals and signed in Hilden on October 5th, 2000.

/s/ Peer Schatz                             /s/ Metin Colpan
----------------                            -------------------
COMPANY                                     MANAGING DIRECTOR

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