The relationship between measures of social desirability and various preventive health behaviors was examined directly for 235 females and 171 males from the British public and 182 females and 49 males from the University of Toronto, Canada. Both simple and partial correlations controlling for age showed that social desirability scores were related to total preventive behavior scores formed on the basis of the responses to 42 items, as well as many of the individual preventive behavior items. To ensure that this relationship was not unique to the present study, the response frequencies for 15 behavior items in this study were compared with those reported by another investigator who also used these 15 behavior items, and were found to be quite similar. Simple and partial correlations controlling for age showed that social desirability scores were significantly correlated with more of these 15 behaviors than one would expect by chance. The implications of the association of social desirability and preventive health behavior for the measurement of preventive health behavior, future research, and health education are discussed.