The list of countries that have openly declared that they possess nuclear weapons includes the United States, Russia, the United Kingdom, France, China, India and Pakistan. North Korea has declared that it does possess nuclear capability, and there has been a confirmed test recently.

The first atomic weapons were developed by the United States of America during World War II. Trinity was the name of its first nuclear weapon which was tested in 1945. Till date, America remains the only country which has utilized nuclear weapons against another nation. Since then, other nations have tested their nuclear weapons. However after the atomic bombing of Hiroshima and Nagasaki by the United States in August 1945, no nation has used nuclear weapons against another nation. The chief arguments against nuclear bombing is that it is inhumane, with massive civilian casualties and that it has had severe and long lasting genetic impact.