Although the dual function of condom use (preventing pregnancy and preventing STDs) is well known, little is known about the determinants of condom use for STD prevention when contraception is not an issue. We compared two intentions to use condoms with a new sex partner: one based on a vignette not mentioning pregnancy risk and one on a vignette explicitly stating there was no risk of pregnancy. We also investigated whether intentions to use condoms change when there is no pregnancy risk, to allow such changes to be predicted from an STD risk-perception perspective. This cross-sectional survey was completed by 151 undergraduate students. The correlation coefficient between the two intentions about condom use approached zero (0.02; p=.783). Logistic regression showed that two STD risk-perception variables distinguished between consistent and non-consistent reporters of their intention to use condoms. Findings are discussed from the perspectives of policy, methodology and theory.