Autologous peripheral blood stem cells transplantation (PBSCT) is a therapeutic option which can be used in various hematological neoplastic disorders; and it can prolong disease free survival and total survival and at times it may be curative. In this study, we investigated variables influencing PBSCT in 91 patients who had undergone PBSCT between 1998 and 2002 in our center, retrospectively. PBSC collection was performed after mobilization with G-CSF or chemotherapy plus growth factor. Only high dose chemotherapy was used for conditioning regimes. The median number of CD34+ was 11.5 x 10(6)/kg. Posttransplant neutrophil engraftment (>500/microL) was requiring a median of 10 days, it was 13 days for platelet engraftment (>20,000/microL). For neutrophil and platelet engraftment, we investigated; sex, age, diagnosis and CD34+ cells, the time interval between diagnosis and transplantation, number of apheresis, conditioning regime, growth factor initiation day as independent variables. In univariate analysis CD34+ cell number (>10 x 10(6)/kg), time interval more than one year between diagnosis and transplantation and BEAM conditioning was found to be significant for neutrophil engraftment. But in multivariate analysis none of them was found to be significant. For platelet engraftment in univariate analysis CD34+ cell number (>7 x 10(6)/kg), primary diagnosis of multiple myeloma initiation day of growth factor (>2 day) was found to be significant. In multivariate analyses only CD34+ cell count was found to be significant (p=0.005). In conclusion, as in previous studies we found that the only predictor of engraftment kinetics was CD34+ cell count.