This study investigated the relationship between personality characteristics and sensation seeking, as well as sex differences in risk-taking behaviors such as substance abuse and unsafe sex. The sample consisted of 47 undergraduate students (22 men and 25 women) at a public, midwestern university. The Sensation Seeking Scale (SSS)-Form V and a personality questionnaire that yields the Big Five personality traits were administered to all participants. Results indicated Extroversion predicted sensation seeking in females only, whereas low Agreeableness and low Conscientiousness predicted sensation seeking in the entire sample. Furthermore, men appeared to be significantly more willing to find interested in taking risks than women. These findings help explain who is most likely to engage in risky behaviors in an undergraduate population, which ultimately could be used to develop more efficacious prevention programs for this population.