There has been increasing interest in autologous peripheral stem cell transplantation (APSCT) in the treatment of malignant disease because it is a convenient method and may have a lower risk of tumor cell contamination than autologous bone marrow transplantation (ABMT). Recently, it is reported that the number of peripheral blood stem cells increase during recovery phase of hemopoiesis after chemotherapy, and further increase is reported on the case of treatment with G-CSF. But influences of G-CSF to the residual malignant cells is still unknown. In this report, we have used clonal cell culture and kappa-lambda imaging (KLI) analysis to trace the level of CFU-GM, BFU-E, and malignant B-cell population (mBp) in peripheral blood before and after treatment with rhG-CSF. The peak level of CFU-GM in peripheral blood was a 2-fold increased when rhG-CSF was administered, and this peak appeared 5-7 days earlier than that in the case without rhG-CSF. MBp was detected in bone marrow, however, no mBp was detected before and after treatment with rhG-CSF in peripheral blood. These findings suggest that APSCT is acceptable for this patient in case of minimal bone marrow involvement. And KLI analysis might be an effective method for detecting residual malignant cells in bone marrow and peripheral blood.