A simple, rapid and sensitive high-performance liquid chromatography (HPLC)-based method with ultraviolet detection was developed for the quantitation of nilotinib, a tyrosine kinase inhibitor, in human plasma. Nilotinib and the internal standard dasatinib were separated using a mobile phase of 0.5% KH(2)PO(4) (pH2.5)-acetonitrile-methanol (55:25:20, v/v/v) on a Capcell Pak MG II column (250 x 4.6 mm) at a flow rate of 0.5 mL/min and optical measurement at 250 nm. Analysis required only 100 microL of plasma and involved a rapid and simple solid-phase extraction with an Oasis HLB cartridge, which gave recoveries from 72 to 78% for nilotinib and from 74 to 76% for dasatinib. The lower limit of quantification for nilotinib was 10 ng/mL. The linear range of this assay was between 10 and 5000 ng/mL (r(2) > 0.9992 for the regression line). Intra- and inter-day coefficients of variation were less than 10.0% and accuracies were within 10.4% over the linear range. Our results indicate that this method is applicable to the monitoring of plasma levels of nilotinib in a clinical setting.