The non-secreting rat myeloma cell line YB2/0 could be separated into different cell fractions by counterflow centrifugal elutriation. The obtained fractions are analyzed by morphology studies, morphometrics, clonogenic assays and flow cytometry. The methodology is extensively described. A separation of different cell fractions according to cell cycle stages was achieved. This implies further application possibilities for clinical use like the in vitro fractionation of autologous bone marrow prior to transplantation in patients with multiple myeloma.