THIS IS THE first report of a series of adults (>16 years of age) with pineoblastomas who had their entire neuraxis staged at the time of diagnosis. Between 1975 and 1992, seven men and four women with histologically proven pineoblastomas were evaluated at the University of California, San Francisco. The median age at diagnosis was 36 years (range, 17–59 yr). All patients presented with symptomatic hydrocephalus. One patient had a complete surgical resection, eight had subtotal resections, and two had biopsies only. One patient refused any treatment or follow-up review and died 6 months after diagnosis. The five patients with positively staged disease had progression either focally or in the spine 8 to 49 months (median, 10 mo) after initial diagnosis and died 1 to 20 months after recurrence; the median overall survival time from the date of surgery was 30 months. In contrast, all five patients with negatively staged disease were alive without disease progression after a median of 26 months of follow-up. Our retrospective review shows that the extent of disease at diagnosis seems to be an important prognostic factor for pineoblastomas, as is true for medulloblastomas and other primitive neuroectodermal tumors. Initial staging should include examination of the cerebrospinal fluid and magnetic resonance imaging of the spine. Although patients with pineoblastomas are often treated with adjuvant systemic chemotherapy after craniospinal irradiation, the benefits of this approach are unclear.