Lisbon Protocol

The Lisbon Protocol to the 1991 Strategic Arms Reduction Treaty was a document signed by representatives of Russia, Belarus, Ukraine, and Kazakhstan that recognized the four states as successors of the Union of Soviet Socialist Republics and all of them assume obligations of the Soviet Union under the START I treaty.

These were the four countries in which strategic nuclear weapons of the former Soviet Union remained. The protocol also committed Belarus, Kazakhstan, and Ukraine to join the Treaty on the Non-Proliferation of Nuclear Weapons as non-nuclear-weapon states, which was completed by 1994. The 1994 Budapest Memorandum implemented the removal of nuclear weapons from Belarus, Kazakhstan, and Ukraine by 1996, in exchange for security guarantees.

The protocol was signed in Lisbon, Portugal, on 23 May 1992.