OBJECTIVE: To review and analyze a contemporary series of 15 neonates who were treated for posterior fossa subdural hematomas (PFSDHs) during the era of computed tomography and magnetic resonance imaging. METHODS: A retrospective chart review identified all neonates with PFSDHs for whom neurosurgical consultations were obtained for treatment planning. RESULTS: There were nine male and six female patients. The mean gestational age was 39 weeks. Nine of the 15 mothers of the patients were primiparous. Instrument-assisted delivery (forceps and/or vacuum extractor) was undertaken for seven patients. The mean birth weight of the infants was 3165 g (range, 2160-3930 g). The mean 5-minute Apgar score was 7.5. Symptoms of PFSDH developed within the first 24 hours of life in 13 neonates. The predominant symptoms and signs were failure to thrive, irritability, seizures, apnea, and bradycardia. Lumbar punctures to rule out central nervous system sepsis were performed in six neonates. Hemograms revealed that six neonates were anemic with low hemoglobins, five had low platelets, and four had abnormal prothrombin and/or partial thromboplastin times at the time of diagnosis. Computed tomography established the diagnosis of PFSDH in all cases. Magnetic resonance imaging was performed for two neonates. The median time to diagnosis by imaging studies was 10 hours after birth. Surgical evacuation of the PFSDHs was performed in eight neonates. Seven neonates were followed conservatively with serial imaging studies. There was no mortality in either treatment group. Follow-up ranged from 2 to 10 years, with a mean of 4.5 years. Functional outcome assessment revealed that seven neonates were neurodevelopmentally normal, three were mildly delayed, two were moderately delayed, and three were profoundly delayed. In addition to traumatic causes of the PFSDHs, three neonates were observed to have coagulation disturbances at birth and one was observed at follow-up to have a posterior fossa medulloblastoma that had bled at birth. CONCLUSION: PFSDHs are rare but important lesions to diagnose early in the neonatal period. Surgery can be life-saving when performed in a timely manner for signs and symptoms of brain stem dysfunction. A search for an underlying cause predisposing to a PFSDH may, on occasion, reveal a coagulation disturbance or a neoplasm that will require additional therapeutic considerations.