['To detect sperm plasma membrane integrity (PMI) of cigarette smoking infertile males using SYBR-14/ PI fluorescent staining and flow cytometry and investigate its clinical significance.', 'We collected semen samples from 132 cigarette smoking infertile men and 70 normal fertile controls, the former divided into a heavy-smoker group (> 20 cigarettes a day, n = 68) and a light-smoker group (< or = 20 cigarettes a day, n = 64). We performed computer-assisted semen analysis of the semen samples, and determined sperm PMI by flow cytometry after rinsing with PBS and staining by SYBR-14/PI, the sperm with normal PMI indicated as the percentage of those emitting green fluorescence (SYBR-14+/PI- %), dead sperm as the percentage of those emitting red (SYBR-14-/PI+), and moribund sperm as the percentage of those emitting both green and red (SYBR-14+/PI+).', 'Both the heavy- and light-smoker groups showed significant differences in SYBR-14-/PI+ % and SYBR-14+/PI- % from the normal controls (P < 0.01 or P < 0.05). SYBR-14+/PI- % was remarkably lower, while SYBR-14-/PI+ % markedly higher in the heavy-smoker than in the light-smoker group (P < 0.05). There was a significant correlation between SYBR-14+/PI- % and sperm motility (r = 0.938, P = 0.000).'] Does [ Cigarette smoking affect sperm plasma membrane integrity ]?