The aim of the study was to assess adherence with antiretroviral medication in a sample of HIV patients in Hong Kong and identify predictors of adherence. The study used a cross-sectional correlational design. Adherence behaviour was assessed with the use of self-reports. Other scales assessed knowledge with HIV medication, coping, health locus of control, anxiety, depression and fatigue. A blood sample was also obtained to assess CD4+ counts and viral load. Sociodemographic characteristics and medical information were obtained from the medical records. A high adherence rate was found in this sample of 136 predominantly Chinese patients. There were only 13.7% of the patients being classified as non-adherent. Predictors of adherence included high self-efficacy in terms of being certain that the medication schedule will be followed all or most of the time as directed, low tension-anxiety scores, and low intensity of nausea and vomiting (R2=0.304). An expanded regression model revealed additional factors influencing adherence, including coping variables, pain and numbness in the hands and feet, age, disease stage, internal locus of control, fatigue, family support and taking medication twice daily. This model explained 49% of the variance in adherence. The results suggest that adherence is a multidimensional concept. Every effort should be made to assess in individuals those variables found to affect adherence and alter them whenever possible. Continuous support of patients and individualized medication programmes that will help patients adjust their treatment to their lifestyle are recommended.