Propionibacterium acnes are gram-positive pleomorphic rods that grow under an anaerobic condition. They are the most frequent inhabitants of sebaceous glands of skin, hair follicles, mouth, upper respiratory tract, and as a frequent contaminant in laboratory cultures. Propionibacterium acnes is an underestimated but significant cause of postneurosurgical infection, especially in the presence of foreign bodies such as shunt systems. We present a rare case with a postoperative subdural empyema in which the only pathogen isolated was Propionibacterium acnes. In our case, the clinical course was atypically rapid. The most effective antibiotic therapy for Propionibacterium acnes infections has not been established. However, high dose penicillin in combination with surgical drainage and removal of foreign bodies is recommended as the treatment of choice.