Abstract The Critically Endangered Antiguan racer Alsophis antiguae is confined to Great Bird Island, a 9.9 ha (24.5-acre) islet off the north-east coast of Antigua in the Lesser Antilles. This island represents well under 0.1 per cent of the species's historical distribution range. During the past 5 years, the total number of racers aged 1 year or more has fluctuated between 51 and 114, and currently stands at approximately 80. Since 1995, the Antiguan Racer Conservation Project (ARCP) has en-deavoured to save this harmless snake from extinction by using a combination of education, conservation breeding, habitat restoration, local capacity building and applied research. The Antiguan racer's ecology and population dynamics have become well understood after 5 years of intensive study, and the species has evidently benefited from the project's rat eradication programme. The snakes are still seriously threatened by other intrinsic and extrinsic factors, however, including inbreeding depression, frequent hurricanes, invasive predators and deliberate killing by tourists, as well as the problem that Great Bird Island is too small to support more than about 100 individuals. This paper describes the activities and impact of this project to date, and outlines a series of conservation activities to safeguard the long-term future of the species, which include reintroduction of the Antiguan racer to restored islands within its former distribution range.