The purpose of this study was to investigate the frequency of CYP2B6 polymorphisms and their influence on plasma concentrations of efavirenz and nevirapine in HIV-infected Chinese patients. After written informed consent, 159 patients were enrolled at Shanghai Public Health Clinical Center. Genotyping for 516 G>T, 785 A>G, 983 T>C, and 1459 T>C polymorphisms in CYP2B6, together with CYP3A4 -392 A>G, CYP3A5 6986 A>G, and ABCB1 (2677 G>T/A, 3435 C>T), were performed. Plasma efavirenz and nevirapine concentrations of 120 patients at steady state were assessed by high-performance liquid chromatography-mass spectrometry. The minor allele frequency for CYP2B6 516 G>T, 785 A>G, 983 T>C, and 1459 T>C was 0.16, 0.24, 0, and 0, respectively; and 0.07, 0.32, 0.15, and 0.35 for CYP3A4 -392 A>G, CYP3A5 6986 A>G, ABCB1 2677 G>T/A, and ABCB1 3435 C>T, respectively. Univariate analysis indicated associations between 516 G>T (P < 0.01) with efavirenz but not nevirapine plasma concentrations. None of other genetic variants was associated with plasma efavirenz or nevirapine concentrations. Although CYP2B6 516 G>T was associated with high plasma efavirenz concentrations, such an association was not evident with nevirapine in this Chinese patient population. CYP3A4 -392 A>G, CYP3A5 6986 A>G, and ABCB1 (2677 G>T/A, 3435 C>T) had no significant impact on plasma efavirenz or nevirapine concentrations.