To compare methods for erythroid differentiation of K562 cells that will be promising in the treatment of beta-thalassemia by inducing gamma-globin synthesis. Cells were treated separately with: RPMI 1640 medium without glutamine, RPMI 1640 medium without glutamine supplemented with 1 mM sodium butyrate, RPMI 1640 medium supplemented with 1 mM sodium butyrate, 25 A mu g cisplatin/ml, 0.1 A mu g cytosine arabinoside/ml. The highest differentiation (84 %) with minimum toxicity was obtained with cisplatin at 15 A mu g /ml. Real-time RT-PCR showed that expression of the gamma-globin gene was significantly higher in the cells differentiated with cisplatin compared to undifferentiated cells (P < 0.001). Cisplatin is useful in the experimental therapy of -globin gene defects and can be considered for examining the basic mechanism of gamma-reactivation.