ObjectivesTo elucidate whether a combination of slow gait speed and depressive symptoms result in higher risk of incident disability in older adults than either symptom individually. DesignProspective cohort study. SettingObu City, Aichi Prefecture, Japan. ParticipantsParticipants were 4038 older adults (48.7% male, mean age = 71 years) who met the study inclusion criteria. MeasurementsLongitudinal data on incident disability were collected up to 33 months [median 31 months (interquartile range 29–32 months)] after baseline. We monitored monthly incident disability, defined as Japanese long-term care insurance certification for personal support or care. Baseline measurements included covariates for incident disability, gait speed, and the Geriatric Depression Scale for assessing depressive symptoms. The associations between slow gait, depressive symptoms, or their co-occurrence, and incident disability were examined. ResultsControl participants were the reference in an adjusted Cox proportional hazard regression model. Participants with co-occurring slow gait and depressive symptoms showed a greater risk of incident disability [hazard ratio (HR) 3.08, confidence interval (CI) 95% 2.00–4.75]. Greater risk was also found for participants with slow gait speed alone (HR 2.44, CI 95% 1.71–3.47) and depressive symptoms alone (HR 1.60, CI 95% 1.01–2.53). ConclusionsOlder adults with both risk factors may require early detection and physical and psychological intervention.