improved access to antiretroviral therapy (ART) has significantly increased the survival and quality of life of HIV-infected persons. Strict adherence to antiretroviral therapy (ART) is crucial if viral suppression must remain optimal. We assessed predictors of adherence to ART among adult patients in Cross River State (CRS), Nigeria. a cross-sectional survey was conducted among 999 adult patients on ART in selected secondary and tertiary health facilities in CRS from January to June 2017. Respondents were recruited using multistage technique. Data were collected using a pre-tested interviewer-administered questionnaire. Adherence was defined as clients taking at least 95% of their pills in the last seven days. Multivariate analysis was performed to determine predictors of adherence at 5% level of significance. majority (70.5%) of the respondents were females with a mean age of 43.7 ± 11.1 years. The self-reported adherence rate was 60.1%. The commonest reasons for non-adherence was client travelling out of home, being busy, forgetting and lack of food. The significant predictor identified in this study was being on first-line drugs (OR=3.677, 95% C.I=2.523-5.358), were 3 times more likely to have good adherence. Predictors of poor-adherence were alcohol intake (OR=0.382, 95% C.I=0.262-0.559), dosing medications (OR=0.502, 95% C.I=0.381-0.661), CD4 cell count ≥ 500 (OR=0.723, 95% C.I=0.543-0.964), poor attitude to HIV status and medication (OR=0.713, 95% C.I=0.512-0.994) and family support (OR=0.736, 95% C.I=0.544-0.995). adherence to ART among clients in this study was fair. Majority of the reasons for poor-adherence were client-related. There is need for targeted counselling to improve adherence.