The W85 was a thermonuclear warhead developed by the United States to arm the Pershing II missile.

[2][3] The Pershing Ia missile was armed with a 400 kilotonnes of TNT (1,700 TJ) W50 warhead.

By the early 1970s, it was clear that this was far too large to allow the missile to be used as a tactical nuclear weapon—at the time, 400 kilotons was larger than many strategic warheads.

The Pershing II had a high-accuracy maneuverable reentry vehicle (MARV) equipped with a radar terminal guidance system, which allowed it to use the lower-yield W85 warhead.

[5] The total weight of the Pershing II warhead section was 591 pounds (268 kg), which included the reentry vehicle.