The article presents comparative data of cytometry estimation of accumulation of daunorubicin and rodamin-123 in cells of peripheralbloodofhealthypeople underincubation ofsubstances in vitro. It is demonstrated that maximal saturation of thrombocytes occurs during the first five minutes, of leukocytes during forty five minutes. The erythrocytes factually never accumulate these compounds. The maximal values of accumulation of substances in leukocytes are characterized by high inter-individual variation. The close correlation (Rs = 0.96-0.98) of parameters of accumulation of substances in lymphocytes and neutrophils testifies the presence ofsimilar mechanisms ofcontrol ofactivity transportation ofxenobiotics in nucleated cells of blood. However, the results of inhibitor analysis of input of Pgp-dependent mechanisms of accumulation of rodamin-123 by leukocytes differ the data received under application of daunorubicin that reflects differences of their intracellular binding sites. The expressed differences between parameters of accumulation ofdaunorubicin and rodamin-123 by leukocytes in various patients determine necessity of individual approach in monitoring of development of medicinal resistance.