Objective The development of subdural abscess following burr hole drainage for chronic subdural hematoma is very rare, and another drainage is usually performed instead of craniotomy. We will discuss the efficacy of craniotomy.Methods We report two cases of subdural abscess following burr hole drainage for chronic subdural hematoma, who were treated by craniotomy in our department.Results We report two cases of subdural abscess following burr hole drainage for chronic subdural hematoma, who were treated by craniotomy in our department.Conclusions Both cases achieved good prognosis, without obvious signs and symptoms of nervous system damage. Conclusions Preoperative imaging evaluation is vital to patients with subdural abscess, and we can select another drainage or craniotomy based on the preoperative imaging features. Antibiotics can be given intravenously at an enough dose.