Background and purpose: Cerebral small vessel disease is common in elderly persons. Patients with dementia or stroke frequently have cerebral small vessel disease and often experience disturbances in the sleep-wake rhythm. It is unknown whether cerebral small vessel disease is related to disturbances in sleep and 24-h activity rhythms. Methods: This study was conducted in the Rotterdam Study. A total of 970 community-dwelling persons (mean age 59.2 years) underwent brain magnetic resonance imaging and actigraphy. Cerebral small vessel disease was defined as white matter lesions (total volume in millilitres) and the presence of cerebral microbleeds and lacunar infarcts. Twenty-four hour activity rhythms and sleep were measured with actigraphy by estimating the instability and fragmentation of the activity rhythm and total sleep time. Sleep quality was assessed with the Pittsburgh Sleep Quality Index. White matter lesions, instability, fragmentation and sleep quality were standardized for analyses. Results: Higher white matter lesion volume (B = 0.09 per SD, 95% confidence interval 0.02; 0.15) and cerebral microbleeds (B = 0.19 per SD, 95% confidence interval 0.02; 0.37) were significantly related to more fragmented 24-h activity rhythms. None of the small vessel disease markers was related to total sleep time or sleep quality. Conclusions: White matter lesion volume and the presence of cerebral microbleeds are related to disturbed activity rhythms. This suggests that subclinical brain damage affects the 24-h activity rhythm.