The association of cigarette smoking with development of hearing impairment (loss of 30 dB at 1000 Hz and 40 dB at 4000 Hz) over a 5-year follow-up was studied in 1554 non-hearing-impaired Japanese male office workers who ranged in age from 30 to 59 years. After controlling for potential predictors of hearing impairment, the relative risk for low-frequency hearing impairment compared with never smokers was 1.12 (95% confidence interval [CI], 0.57 to 2.17) for ever-smokers, 1.21 (95% CI, 0.65 to 2.25) for current smokers of 1 to 20 cigarettes/day, 1.35 (95% CI, 0.70 to 2.61) for current smokers of 21 to 30 cigarettes/day, and 1.82 (95% CI, 0.98 to 3.38) for current smokers of 31 or more cigarettes/day (P for trend = 0.063). The respective multivariate-adjusted relative risks for high-frequency hearing impairment compared with never smokers were 1.70 (95% CI, 0.85 to 3.40), 1.82 (95% CI, 0.92 to 3.59), 2.00 (95% CI, 0.98 to 4.08), and 2.20 (95% CI, 1.09 to 4.42) (P for trend = 0.025). As the number of pack-years of exposure increased, the risk for high-frequency hearing impairment increased in a dose-dependent manner (P for trend = 0.011), but the risk for low-frequency hearing impairment did not (P for trend = 0.172). Our results indicate that cigarette smoking is highly associated with development of high-frequency hearing impairment in Japanese male office workers.