Objectives. This study undertook to examine relationships between nonsedentary activity level, time spent watching television (TV)/videocassette recorder (VCR), and risk of overweight among men. Methods. Men participating in the Health Professionals Follow-Up Study were mailed surveys. Cross-sectional analyses examined the prevalence and odds of being overweight; prospective analyses determined cumulative incidence rates and relative risks of becoming overweight over 2 years of follow-up. Results. Cross-sectionally, odds of being overweight were 50% (95% confidence interval [CI] = 45%, 55%) lower for men in the highest quintile of nonsedentary activity level when compared with men in the lowest quintile. Among men watching 41 or more hours of TV/VCR per week, the odds of being overweight were 4.06 (95% CI = 2.67, 6.17) times greater than those for men watching no more than 1 hour per week. Prospectively, higher levels of nonsedentary activity and lower levels of TV/VCR viewing were independently associated with lower relative risks for becoming overweight between survey years. Conclusions. Both a lack of nonsedentary activity and time spent watching TV/VCR contribute to the development of overweight in men. Sedentary and nonsedentary activities represent separate domains, each with independent risks for overweight.