Exhibit 10.4.6

SIXTH AMENDMENT TO THE 1994 STOCK OPTION PLAN OF BIO-RAD LABORATORIES, INC.

Bio-Rad Laboratories, Inc., a corporation organized under the laws of the State
of Delaware (the “Corporation”), has previously adopted the Bio-Rad
Laboratories, Inc. 1994 Stock Option Plan (as amended from time to time, the
“Plan”). Section 9 of the Plan allows the Board of Directors of the Corporation
to amend the Plan in certain respects at any time or from time to time.
In order to amend the Plan in certain respects, this Amendment to the Plan has
been adopted by a resolution of the Board of Directors of the Company on
December 7, 2011, effective as set forth below. This Amendment to the Plan,
together with the Plan, constitutes the entire Plan as amended to date.
1.    Effective as of December 12, 2011, Section 7(b) of the Plan is hereby
amended to read in its entirety as follows:
(b) Each option shall provide that the purchase price of the shares as to which
such option shall be exercised shall be paid at the time of exercise by such
methods as the Committee may approve from time to time. The following forms of
payment are currently available: (1) cash; (2) by withholding shares of the
Company's Stock that would otherwise be issued upon the exercise of the option;
(3) by the delivery to the Company or its designated agent of shares of the
Company's Stock held for such period of time as may be required by the Board in
order to avoid adverse accounting consequences, or (4) other property acceptable
to the Board (including through the delivery of an irrevocable notice that the
optionee has placed a market sell order with a broker with respect to shares of
Stock then issuable upon exercise of the option, and that the broker has been
directed to pay a sufficient portion of the net proceeds of the sale to the
Company in satisfaction of the option purchase price; provided that payment of
such proceeds is then made to the Company upon settlement of such sale). Any
shares or other securities so withheld or tendered will be valued by the Company
as of the date they are withheld or tendered.
2.    Effective as of December 12, 2011, Section 7(j) of the Plan is hereby
amended to read in its entirety as follows:
j.     Tax Withholding for Nonqualified Stock Options. The Board may provide
that the payment to the Company (or other employer corporation) of all amounts
which it is required to withhold under federal, state or local law in connection
with the exercise of a Nonqualified Stock Option be satisfied in the following
manner: (1) cash; (2) by withholding shares of the Company's Stock that would
otherwise be issued upon the exercise of the Nonqualified Stock Option, subject
to applicable laws and regulations concerning withholding; (3) by the delivery
to the Company or its designated agent of shares of the Company's Stock held for
such period of time as may be required by the Board in order to avoid adverse
accounting consequences, or (4) other property acceptable to the Board
(including through the delivery of an irrevocable notice that the optionee has
placed a market sell order with a broker with respect to shares of Stock then
issuable upon

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exercise of the option, and that the broker has been directed to pay a
sufficient portion of the net proceeds of the sale to the Company in
satisfaction of the amount required to be withheld in connection with the
exercise of the option; provided that payment of such proceeds is then made to
the Company upon settlement of such sale). Any shares or other securities so
withheld or tendered will be valued by the Company as of the date they are
withheld or tendered. Notwithstanding any other provision of this Plan, the
number of shares of Stock which may be withheld from the number of shares
otherwise issuable upon the exercise of a Nonqualified Stock Option under the
Plan in order to satisfy the holder's federal and state income and payroll tax
liabilities with respect to the exercise of such Nonqualified Stock Option shall
be limited to the number of shares which have a fair market value, as determined
by the Company as of the date they are withheld, equal to the aggregate amount
of such liabilities based on the minimum statutory withholding rates for federal
and state tax income and payroll tax purposes that are applicable to such
supplemental taxable income.
3.    Effective as of December 12, 2011, Section 5 of Annex B of the Plan is
hereby amended to read in its entirety as follows:
5.     Payment of Purchase Price. On exercise of the Option, the Optionee shall
pay the Purchase Price of the Shares as to which the Option is exercised with
such methods as the Committee may approve from time to time. The following forms
of payment are available: (1) cash; (2) by withholding Shares of Stock that
would otherwise be issued upon the exercise of the Option; (3) by the delivery
to the Company or its designated agent of Shares of Stock held for such period
of time as may be required by the Board in order to avoid adverse accounting
consequences, or (4) other property acceptable to the Board (including through
the delivery of an irrevocable notice that the Optionee has placed a market sell
order with a broker with respect to Shares of Stock then issuable upon exercise
of the Option, and that the broker has been directed to pay a sufficient portion
of the net proceeds of the sale to the Company in satisfaction of the Option
Purchase Price; provided that payment of such proceeds is then made to the
Company upon settlement of such sale).
4.    Effective as of December 12, 2011, Section 7 of Annex B of the Plan is
hereby amended to read in its entirety as follows:
5.     Withholding. The Optionee may provide that the payment to the Company (or
other employer corporation) of all amounts which it is required to withhold
under federal, state or local law in connection with the exercise of the Option
be satisfied in the following manner: (1) cash; (2) by withholding Shares of
Stock that would otherwise be issued upon the exercise of the Option, subject to
applicable laws and regulations concerning withholding; (3) by the delivery to
the Company or its designated agent of Shares of Stock held for such period of
time as may be required by the Board in order to avoid adverse accounting
consequences, or (4) other property acceptable to the Board (including through
the delivery of an irrevocable notice that the Optionee has placed a market sell
order with a broker with respect to Shares of Stock then issuable upon exercise
of the Option, and that the broker has been directed to pay a sufficient portion
of the net proceeds of the sale to the Company in satisfaction of the Option
Purchase Price; provided that

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payment of such proceeds is then made to the Company upon settlement of such
sale). Any shares or other securities so withheld or tendered will be valued by
the Company as of the date they are withheld or tendered. The right to so
withhold or tender shares shall relate separately to any increment of the
Option.
  
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Executed on December 12, 2011
BIO-RAD LABORATORIES, INC.

By:

/s/ Sanford S. Wadler
Vice President & General Counsel

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