Thirteen of 394 (3.3%) regularly dialyzed patients of the Regional Kidney Disease Program developed subdural hematoma. The following factors contributed to formation of subdural hematoma: head trauma, ultrafiltration to control excessive accumulation of fluid and hypertension, anticoagulants, and frequent vascular access infection and clotting. Neurologic symptoms and signs, which may be similar to dialysis disequilibrium, aid only in signifying the presence, not the ultimate localization, of subdural hematoma. Our experience underscores the frequency of bilateral disease, irrespective of neurologic findings. Skull films, lumbar puncture, and electroencephalography were of little diagnostic help. Although valuable and safe, brain scanning was not as useful as desired due to occurrences of false-negative studies and failure to identify bilaterality of lesions. Cerebral angiography was always diagnostic. Surgical intervention yielded disappointing results, and only 2 patients (15%) survived. A review of 9 other patient reports is included.