['The aim of this study was to assess the rate of adherence to medications amongst psychiatric outpatients in Nigeria and examine factors associated with medication nonadherence amongst this group.', 'Psychiatric outpatients (n=342) from three centres were assessed for medication adherence using the Morisky Medication Adherence Questionnaire. Details regarding sociodemographic variables (age, sex, education, religion, marital status, employment, income, medication cost), illness related variables (diagnosis, duration, number of episodes/admissions, insight, severity of symptoms, mental state, functional status), medication related variables (type, mode of administration, side effect, attitude to medication) and perception related variables (self-stigma, perceived causation and prognosis) were also obtained.', 'There were 76 participants (22.2%) with good medication adherence, 102 (29.8%) with moderate adherence and 164 (48.0%) with poor adherence. The significant independent correlates of poor medication adherence included being employed [odds ratio (OR) 3.42, 95% confidence interval (95% CI) 2.17-5.39], poor social support (OR 5.86, 95% CI 2.87-12.17), high self-stigma (OR 4.70, 95% CI 2.24-9.96) and perceived spiritual causation of mental illness (OR 3.74, 95% CI 1.87-7.74).'] Does prevalence and correlate of poor medication adherence amongst psychiatric outpatients in southwestern Nigeria?