The treatment results of 96 patients with Philadelphia-positive chronic myeloid leukemia (CML) in accelerated phase (AP) were reviewed retrospectively. Treatment of AP consisted of allogeneic bone marrow transplantation in 20 (14 related and 6 unrelated donors) or conventional chemotherapy (CC) in 76 patients. Three main treatment strategies were followed in the CC group: continuation (group A) or dose escalation (group B) of chronic phase therapy or change of chronic phase therapy to hydroxyurea (group C). Median survival was 7.0 months in group A (range 1.8-110), in group B 8.3 months (range 0.9-40) and in group C 9.6 months (range 1.5-47.6), p=0.89. Survival in CC was dependent on response to therapy as the achievement of a second chronic phase was significantly associated (p<0.001) with a longer median survival (21 months) compared with stable accelerated phase disease (11 months) or treatment failure (5 months). Median survival in the BMT group was 16.7 months (range 5-77), the 5-yr probability of relapse was 25% and the 5-yr disease-free survival was 36%. For patients <55 yr median survival after BMT was significantly prolonged compared with median survival after CC (n=45, 8.3 months, p=0.008). After developing criteria of AP, median survival in our analysis has been less than 1 yr. The results of conventional chemotherapy in the treatment of accelerated phase CML are disappointing. If a suitable donor is available allogeneic BMT should be performed without delay in patients with AP.