This investigation examined the dimensionality of personal health practices among 1,171 men and 1,854 women included in a national probability sample of adults 20 to 64 years of age living in the coterminous United States. Data on a wide range of personal health behaviors were collected in the 1979 National Survey of Personal Health Practices and Consequences. I used gender-specific factor analyses to uncover the underlying domains of 10 different types of health behavior. I identified four subsets of personal health practices: (1) passive-risk behavior (i.e., low levels of leisure-time physical activity, poor dental care, poor nutritional habits, infrequent seat belt use, and poor use of preventive medical services); (2) active-risk behavior (i.e., cigarette smoking, alcohol use, and coffee consumption); (3) sleeping behavior; and (4) behavior related to maintaining desirable weight. Internal consistency analyses assessed the stability of the two primary subsets of behavior for different gender, age, and education groups. Women were relatively stable in their tendencies toward both passive-risk and active-risk behavior, regardless of age or education. Older men had more consistent involvement in passive-risk behavior but less consistent active-risk behavior. With higher education, men were more consistent in both passive-risk and active-risk behavior, reflecting more positive health practices.