Introduction Lifetime prevalence of depression varies across countries and different populations. Depression is a common comorbidity of physical illness. Patients with depression are known to present with somatic symptoms. Depression is under-diagnosed in primary care settings.Objectives To estimate the prevalence of depression in patients attending the outpatient department (OPD) of a tertiary care hospital in the Western Province of Sri Lanka.Methods A cross-sectional descriptive study was conducted in the OPD of the National Hospital of Sri Lanka (NHSL). Sample size was 205. Every fifth patient aged between 18 and 60 years who attended the OPD was recruited until the required number was met. Centre for Epidemiologic Studies Depression Scale (CES-D) was used to identify depression.Results There were 114 (55.6%) females. Mean age was 50 years (SD 13.68 Conclusions Prevalence of depression in outpatients is similar to that reported in other parts of the world. None of the patients with depression presented seeking help for depressive symptoms.