Up to now, there is not yet any research on determining the percentage of and factors related to ARV adherence among HIV patients. Objectives: To determine the percentage of and factors related to ARV adherence among HIV patients aged from 16 years old in Can tho city in 2009Method: The cross-sectional study method recruited 267 regularly re-examined HIV / AIDS patients registered 6 months or more with quota sampling method at 5 OPCs in Can Tho city in March 2009.