Gangliogliomas account for 1-4% of all pediatric CNS tumors. We reviewed the records of 123 patients treated at the Children's Hospital of Philadelphia between 1974 and 1995. Ninety-nine patients were eligible for review with complete medical records. The mean age was 9.5 years with 52% females. The mean follow-up was 3.7 years. The most common presenting symptom was seizures (49%). The mean length of symptoms to diagnosis was 24.4 months. Complex partial seizure was the most frequent seizure type (60%). Electroencephalograms were abnormal in 36%. The majority of gangliogliomas were in the temporal lobes (38%), with other sites in the parietal (30%) and frontal lobes (18%). All patients had abnormal nonspecific neuroimaging studies. Nine received chemotherapy, and 21 were treated with radiotherapy. Postoperatively, 78% were seizure free on no medication, 18% had improvement of seizure control, and 4% had stable seizure events. Nine died of disease. Gangliogliomas are benign tumors that frequently present with seizure disorders and nonspecific electroencephalographic and neuroimaging studies. Complete surgical extirpation of these tumors provides improved seizure control in most patients and a short course of antiepileptic medical therapy. Adjuvant therapy including radiotherapy and chemotherapy is limited to recurrent disease not amenable to reoperation.