The interpartner concordance of self-reported sexual behavior among co
llege dating couples (N = 119 couples, total N = 238) was assessed usi
ng self-administered questionnaires. Moderate to high agreement (great
er than or equal to 75%) was found for (a) a range of sexual behaviors
, including all types of penetrative intercourse; (b) behaviors relate
d to vaginal and oral intercourse (e.g., condom use, alcohol use); and
(c) pregnancy-prevention discussion. Partners' reports of when they f
irst met, first dated, and began steadily and exclusively dating were
significantly correlated (all ps <.001). In contrast, less agreement w
as observed for the occurrence of safer sex discussion beyond pregnanc
y prevention (e.g, past sexual histories; <75%) and sexual behaviors i
nvolving the anus and men's genitals (<60%) primarily because of men's
failure to report these behaviors. Participants had moderate awarenes
s of their partner's attitudes toward casual sex, but low awareness of
their attitudes toward condom use and sexual responsibility. Greater
concordance about sexual and safer sex behavior was generally present
in couples in which the male partner was younger and had a restricted
sociosexuality. Men who were virgins prior to their current relationsh
ip and/or who had specifically discussed the woman's past sexual histo
ry had greater knowledge about their partner's past and concurrent sex
ual behavior. Methodological and applied implications of these finding
s for both clinical and empirical sexuality domains are discussed.