The haematological recovery time, infection rate and supportive care requirements of patients receiving recovery phase autologous peripheral blood stem cell transplants (APBSCT)(n= 38), autologous bone marrow transplants (autoBMT)(n= 13) and allogeneic bone marrow transplants (alloBMT)(n= 14) were compared with respect to the time post-transplant to reach 0.1, 0.5 and 2.0 x 10 (9) neutrophils/l and 50 and 150 x 10 (9) platelets/l, the length of hospitalization, fever and antibiotic use, the incidence of documented infection and the number of red cell and platelet transfusions. The APBSCT group had a significantly more rapid recovery of neutrophils and platelets and their supportive care requirements were significantly less than the autoBMT and the alloBMT groups. There was no difference between the latter two groups. The most significant variables contributing to the differences in haematological recovery times were the granulocyte-macrophage progenitor (CFU-GM) dose infused and, to a lesser extent, patient age. The APBSCT group received a higher CFU-GM dose of 87+/-12 x 10 (4)/kg BW compared with 12+/-5 and 17+/-3 x 10 (4)/kg BW in the autoBMT and the alloBMT groups, respectively (p= 0.0001). Patient age showed a negative correlation with the rate of recovery because the APBSCT group, which recovered faster was also older (48+/-2 years, compared with 33+/-3 and 31+/-2, respectively, p= 0.0001). On multivariate analysis, CFU-GM dose was the only variable to show a significant correlation with all the haematological recovery endpoints studied in these 65 patients.(ABSTRACT TRUNCATED AT 250 WORDS)