The outcome of a 29-day residential addiction treatment programme for persons from Antigua and Barbuda with addiction to drugs or alcohol was assessed. All 100 patients entering the drug and alcohol treatment programme at Crossroads Centre Antigua between November 1998 and October 2002 were included. All patients were assessed with regards to drug or alcohol use or abstinence in November 2002 using telephone and mail follow-up as well as informal follow-up with families and other community contacts. Crossroads Centre Antigua is a 35 bed, 29-day residential treatment centre for drug and alcohol addiction serving patients from developed countries (85%) and from the Caribbean region (15%). Patients records were also reviewed to obtain age, gender, ethnicity, drug of choice, years of problematic use, completion of the 29 day programme, family member participation at Crossroads Centre Antigua (a four-day programme) and acceptance of halfway house placement. Of the 100 Antiguan patients admitted, 46 (46%) were abstinent (non-relapsers) at average 20.7 ± 14.7 months after treatment. Abstinence did not have to be continuous. Forty-nine were known to be using drug or alcohol (49%) and five (5%) were lost to follow-up and considered to be using drugs (relapsers). Age (37.5 vs 41.1 years), gender (28% vs 22% female), ethnicity (87% vs 87% Afro-Caribbean), years of harmful use (12.7 vs 12.5 years) did not differ significantly between relapsers and non-relapsers. Crack cocaine use (67% vs 65%) and alcohol use (26% vs 31%) as primary addiction did not differ significantly between relapsers and non-relapsers. Relapsers were significantly less likely to complete the 29- day programme (81% vs 100%, p < 0.01), have family members participate at Crossroads (32% vs 54%, p < 0.05) or accept halfway house placement (4% vs 54%, p < 0.001). In conclusion, abstinence was achieved in 46% of those entering treatment, in 51% completing treatment, in 60% whose families participated and in 92% of those accepting halfway house placement.