We retrospectively analysed the factors that influenced rate of haemopoietic recovery (HR) in 243 patients after transplantation with chemotherapy-mobilised autologous peripheral blood progenitor cells (PBPC). Approximately half the patients also received haemopoietic growth factors (HGF) for mobilisation. Conditioning for transplantation was with either chemotherapy alone or chemotherapy plus total body irradiation (TBI). Median time to recovery of granulocytes > or = 0.5 x 10(9)/l was 13 days (range 7-93 days) and of platelets > or = 50 x 10(9)/l 14 days (7-440). Speed of HR was greater, both for neutrophils and platelets for patients who received more rather than less CFU-GM than our median value of 18.9 x 10(4)/kg (P < 0.0001 in both instances) and more rather than less CD34-positive cells than our median value of 8.8 x 10(6)/kg (P < 0.0001 and P < 0.0005, respectively). For granulocyte recovery, in the multivariate analysis the dose of infused CFU-GM (P = 0.05) and the use of HGF for both mobilisation and post-transplantation (P < 0.0014) were significant positive factors. For platelet recovery in the multivariate analysis the dose of infused CFU-GM (P < 0.0016) was a positive factor. The use of busulphan and of TBI were significant adverse factors for rate of platelet recovery (P = 0.005 and 0.0004, respectively). When compared with non-HGF-mobilised PBPC, HGF-mobilised PBPC reduced the number of days of hospitalisation (28 vs 24, P = 0.0001) and of treatment with intravenous antibiotics (15 vs 11, P = 0.0004). These findings emphasise the importance of cell dose in accelerating haemopoietic recovery after autologous blood stem cell transplantation.