This study compared residual depressive and somatic symptoms and functional impairment between remitted and partially remitted patients with major depressive disorder (MDD), and explored the associations of functioning with demographic and clinical characteristics including residual depressive symptoms. Altogether, 1503 outpatients with MDD formed the study sample. Residual symptoms and psychosocial functioning were measured using standardized instruments. Approximately half (51.2%) of the patients who responded to antidepressant treatment achieved remission ('remitters'), while the rest who responded to treatment achieved only partial remission ('non-remitters'). Residual mood symptoms in remitters included sleep disturbances (66.6%), fatigue (32.3%), decreased concentration (31.3%), appetite/weight disturbances (28.8%), psychomotor changes (23.2%), sad mood (21.9%) and loss of interest (21.1%) measured by the Quick Inventory of Depressive Symptomatology-Self-Report. Residual somatic symptoms included headache (31.9%), intestinal complaints (31.3%), heart pounding/racing (26.3%), gastric complaints (22.3%), dizziness (22.2%) and stomach pain (20.6%) measured by the Patient Health Questionnaire-15. Such residual symptoms were even more frequent in the 'non-remitters' group. Residual symptoms of fatigue, psychomotor changes, sleep disturbance and appetite/weight disturbance contributed to impairment of all functional domains. Given the negative impact of residual symptoms on psychosocial functioning, more attention needs to be paid to the assessment and treatment of residual depressive symptoms.