BackgroundPrevious studies have shown that knowledge of contraceptives, especially among the youth in universities, remains limited, and the rate of premarital sexual activity, unwanted pregnancies, and illegal abortions remains higher among university students. This study aimed to assess contraceptive knowledge, sexual behavior, and factors associated with contraceptive use among female undergraduate university students in Kilimanjaro region in Tanzania.MethodsA cross-sectional analytical study was conducted from May to June 2015 among undergraduate female students in four universities in Kilimanjaro region. A self-administered questionnaire was given to the participants. Data analysis was performed using Statistical Package for Social Sciences. Descriptive statistics were used to summarize the data. An odds ratio with 95% confidence interval for factors associated with modern contraceptive use was computed using multiple logistic regression models. A P-value of <5% (two-tailed) was considered statistically significant.ResultsA total of 401 students were involved in the study. Two-thirds (260, 64.8%) of the participants had had sexual intercourse. The majority (93.8%) of the participants had knowledge of contraception. One hundred and seventy-five (43.6%) sexually active women reported that they used contraceptives in the past, while 162 (40.4%) were current contraceptive users. More than half (54.2%) of the sexually active group started sexual activity between the ages of 20–24 years. The most popular methods of contraception used were condoms, withdrawal, and periodic abstinence. The main sources of information about contraception were friends, television, and health care workers (44.8%, 40.3%, and 39.0%, respectively).ConclusionMost of the participants had knowledge of contraception. However, the rate of contraceptive use was low. The majority of the respondents were sexually active and started sexual activity at >18 years of age. Hence, advocacy for adolescent reproductive health education to promote the use of the available contraceptive services among university students is needed.