Mutual Nuclear Warhead Testing Moratorium Act

Mutual Nuclear Warhead Testing Moratorium Act - Expresses the sense of the Congress that the President should declare that the United States: (1) will, as soon as in-country reciprocal monitoring arrangements are implemented, stop testing nuclear warheads; and (2) will invite the Soviet Union to stop testing nuclear warheads and meet with the United States to enter into negotiations for the conclusion of a Comprehensive Test Ban Treaty at the earliest possible date. Declares that the United States should continue the cessation of the testing of nuclear warheads so long as the Soviet Union refrains from the testing of nuclear warheads and substantive Comprehensive Test Ban Treaty negotiations are in progress.

Expresses the sense of the Congress that during such cessation the President should seek resumption of the comprehensive test ban talks.

Prohibits the United States from obligating or spending any money for testing nuclear warheads outside a designated test area or for testing certain larger warheads within such a test area during the 12-month period beginning 90 days after enactment of this Act if the President does not declare a cessation of nuclear testing. Declares that such prohibition shall cease to apply if the President certifies that: (1) the Soviet Union has carried out such tests; or (2) after the prohibition takes effect, the Soviet Union refuses to accept and implement reciprocal in-country monitoring arrangements. Sets forth information to be included in such certification. Declares that the limitation on nuclear explosions shall be supplanted by a U.S.-Soviet agreement establishing significant limits on nuclear explosions that is negotiated after enactment of this Act.

Requires the President to report annually to the Congress on progress in negotiating a U.S.-Soviet Comprehensive Test Ban Treaty.