Background. The regimen of procarbazine, CCNU, and vincristine is active against gliomas. Previous attempts at dose-intensification have been unsuccesful because of delayed and cumulative myelosuppression. We sought to determine whether peripheral blood stem cell (PBSC) infusions would allow dose-escalation and time compression. Procedure. Eleven patients, age 2.8-35.9 years, with newly diagnosed (n = 10) or recurrent (n = 1) gliomas underwent PBSC harvesting after mobilization with G-CSF. Chemotherapy consisted of CCNU 130 mg/m 2 on day 0, vincristine 1.5 mg/m 2 on days 0 and 7, and procarbazine 150 mg/m 2 on days 1-7. PBSCs were reinfused on day 9 of each course. Four courses of chemotherapy were administered 28 days apart or when counts recovered. Involved field radiation was administered to newly diagnosed high-grade glioma patients following recovery from chemotherapy. Results. Compared to the standard PCV regimen given every 6 weeks, dose intensity received was 1.7-and 1.8-fold greater for CCNU and procarbazine. Chemotherapy was delivered on time in 33/41 (80.5%) courses. Four courses (9.8%) were complicated by absolute neutrophil counts <200/ยตL; platelet nadirs < 50,000/ยตL occurred in two courses (4.9%). Fever with neutropenia complicated three courses. Eight of 9 patients with measurable disease had an objective decrease in tumor size and/or decreased enhancement. Median survival for patients with high-grade gliomas (n = 6) was 13 months. Conclusions.