The objectives were to determine the differences in depressive symptoms and depression between rheumatoid arthritis (RA) and osteoarthritis (OA) patients, and to analyse the contribution of sociodemographic and clinical variables to depression in RA patients. The responses of 60 Egyptian RA patients and 40 patients with OA of the knees to the Symptom Checklist-90-R Depression subscale were compared. The proportions of patients from both groups confirmed by a psychiatric interview to be clinically depressed according to the DSM-III-R criteria were also compared. The contributions of sociodemographic and disease variables to depressive symptoms and clinical depression in RA patients were explored by multiple linear and logistic regression, respectively. RA patients showed significantly higher depression scores than OA patients (P = 0.001). The difference was unaffected by controlling for the effects of age, sex, disease duration and the sociodemographic covariates. A depressive disorder was clinically confirmed in 23% of RA patients and 10% of OA patients. The erythrocyte sedimentation rate (ESR), being unmarried and an urban residence were significant predictors of depressive symptoms (P < 0.05), while being unmarried (P < 0.05, OR = 2.1) and HAQ disability (P < 0.01, OR = 3.8) were significant predictors of clinical depression in RA patients. RA patients have significantly more depressive symptoms and tend to be more clinically depressed than OA patients. The contribution of some sociodemographic and clinical variables to depression in RA patients was modest, albeit significant.