The Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994, is a 6-year survey conducted by the National Center for Health Statistics. Included in NHANES III is data on the cigarette smoking status of U.S. noninstitutionalized civilians obtained through household interview surveys. NHANES III data consist of two data sets: Phase 1 (1988-1991) and Phase 2 (1992-1994). To estimate the prevalence of cigarette smoking across occupational groups and compute standard errors, we analyzed NHANES III-Phase I data with SUDAAN, a statistical software which incorporates sample weights. Based on the 9,477 sampled adults, 20 years of age and older, the overall prevalence of cigarette smoking was 30.9% (95% CI=28.6-33.1). Cigarette smoking prevalence was significantly higher (p<0.001) among blue-collar workers (44%, 95% CI=40.3-47.7) than white-collar workers (25.7%, 95% CI=22.9-28.5). Among occupational groups of which more than 30 employees were sampled, cigarette smoking was most prevalent among construction laborers (54.6%), where-as the lowest smoking prevalence was found among freight and material handlers (12.7%). These findings provide information useful for targeting educational activities focusing on adverse health effects of cigarette smoking and smoking cessation programs.