With the increasing prevalence of premarital sex among college students in China, our aim was to examine prevalence and determinants of condom use among sexually active female undergraduates at 16 university campuses in Wuhan. Questionnaires were distributed to 5076 unmarried female undergraduates, recruited using randomized cluster sampling by type of university and student major and grade, and anonymously completed questionnaires were received from 4769 (94% of enrollees). The complex samples logistic regression was used to examine factors associated with condom use, yielding odds ratios and 95% confidence intervals. Of 4769 female students, 863 (18.1%) reported ever having sexual intercourse. Of these, 19.8% used a condom in their first sexual encounter, and these students were more likely to age 20 or older at first intercourse, and less likely to live in countryside during middle school period, and majoring in the arts. Fully 30% of those having intercourse reported never or seldom or sometimes using condoms in the past 12 months. Students using condoms consistently in the past 12 months were more likely majoring in science and technology, to believe that condoms are the safest way to prevent STD and unwanted pregnancy, and to have used a condom at first intercourse; they were less likely to live in countryside during middle school period, and to report multiple sexual partners since initiating sexual behavior. These results suggested that a larger subset of Chinese female undergraduates is engaged in unprotected, premarital sex, and interventions provided for them should stress the importance of delaying sexual initiation, using condoms from the very first sexual encounter, and consistently using condoms after initiating sex.