We investigated the association between the MDR1 C3435T polymorphism and P-glycoprotein function of leukemic blasts as well as clinical outcomes in 200 patients with AML, excluding the M3 subtype. The CC, CT and TT genotype frequencies of the C3435T polymorphism among patients were 71, 93 and 36, respectively. The C3435T polymorphism genotypes did not have influence on the P-glycoprotein function of leukemic blasts. Complete remission rates and overall, relapse-free and event-free survival rates were not significantly different among the C3435T polymorphism genotypes. In conclusion, the MDR1 C3435T polymorphism does not appear to have significant clinical implications in AML.