The countries include North Korea, Syria and Iran, US undersecretary of state and arms control envoy John Bolton announced on Thursday.
"We are particularly pleased that Libya is now committed to ending all military trade with states of serious weapons of mass destruction proliferation concerns," Bolton told reporters, announcing details of an official Libyan statement on the issue.
Libya "has assured the United States and the United Kingdom that its renunciation of all military trade with states with serious WMD concerns include North Korea, Syria and Iran", he said.
"All three of these countries are indeed states of very great proliferation concern especially North Korea which uses its exports of military technology to finance other dangerous activity," Bolton added.
"Libya's renunciation of military relationship with such proliferators is an important step forward," he said.
Libya has been moving to rejoin the world community since it agreed in December to shelve its weapons of mass destruction programmes.
It also agreed to compensate the families of those killed in the bombings of a PanAm jumbo jet over Scotland in 1988 and a French airliner over the Niger desert in 1989, which were carried out by Libyan agents.