The purpose of this study was to evaluate the efficacy of high-dose chemotherapy with busulfan (Bu), melphalan (Mel), and thiotepa (TT), and of autologous peripheral blood stem cell (PBSC) infusion in patients with aggressive non-Hodgkin's lymphoma (NHL) or relapsed Hodgkin's disease (HD). Forty patients, 23 with intermediate (n= 18) or high-grade (n=5) NHL and 17 with HD received Bu (12 mg/kg), Mel (100 mg/kg), TT (450-500 mg/m2) [corrected], and autologous PBSC infusion. Of 27 patients with more advanced disease, 16 had primary refractory disease, 8 were in refractory relapse, and 3 were in third remission. Of 13 patients with less advanced disease, 7 were in untreated or responding first relapse and 3 were in second remission, whereas 3 with high-grade NHL were in first remission. Twenty-nine patients (73%) had received prior radiotherapy (RT) prohibiting a total-body irradiation (TBI)-based conditioning regimen. The projected 2-year probabilities of survival, event-free survival, and relapse for all patients were 0.60, 0.46, and 0.31 (0.85, 0.85, and 0.15 for patients with less advanced disease and 0.48, 0.30, and 0.37 for patients with more advanced disease). The probability of nonrelapse mortality in the first 100 days was 0.17. Severe idiopathic pneumonia syndrome was not observed in any patients with less advanced disease and in only one patient with more advanced disease. A regimen of BuMelTT is well tolerated in patients with aggressive NHL or relapsed HD, and results obtained to date are at least equivalent to other published regimens, including TBI-based regimens. This regimen appears to be a particularly attractive alternative for patients who have already received dose-limiting RT and should be evaluated further in prospective, randomized studies.