In 2011, several months after a popular revolt overturned the Gaddafi regime in Libya, Libya's new National Transitional Council announced the discovery of what was later confirmed to be an undeclared stockpile of chemical weapons. This was a startling announcement to many observers, since Libya had publicly renounced its weapons of mass destruction (WMD) programmes in 2003 and had apparently dismantled the programmes soon after. Although the Libyan case had repeatedly been referred to as a positive ‘model’ for nonproliferation—an instance where a country had voluntarily and peacefully rolled back its WMD programs—this recent discovery forces us to wonder whether the Libyan ‘model’ really was as successful as initially described. This article examines the successes, challenges and lessons that can be learned from the Libyan case of WMD renunciation and verification. As one model of cooperative verification, the Libyan case highlights not only the opportunities afforded by monitoring and verification regimes, but also some of the difficulties that any such regime will encounter in real-world circumstances, however positive.