The two atomic bombs dropped on Japan at the end of World War II have been the only two atomic or nuclear weapons deployed in an aggressive manner.

There have been fatal nuclear weapons-related accidents, and there have been accidents that came very close to nuclear detonations on the territory of another state, and there have been instances of deaths caused by nuclear testing, and there have been very close calls (near-miss nuclear war scenarios)... but so far, Nagasaki is, thankfully, the last bomb to have been used against an intentional way to end life.