The study aimed to explore knowledge, attitudes and behaviors of premarital sex and its associated factors among bedsit-living students. A community-based cross-sectional study was conducted in Hue city, Vietnam in 2015. Multi-stage cluster sampling was used to recruit students. Data were collected by using a self-administered questionnaire at participant's room. A total of 730 students (men/women: 44.2%/55.8%, mean age: 20.9 years) were enrolled. Prevalence of premarital sex was 11.9% with an average age of first sexual intercourse at 19.8 ± 2.2 years. For premarital sex, 13.3 to 19.5% students did not have enough knowledge of reproductive health and safe sex, 34.1% agreed on different situations. Male students accepted premarital sex more than female students did (45.8% vs. 24.8%, p < 0.001,  2). Gender, age group, marital status, knowledge of consequences of premarital sex and knowledge of STDs prevention were associated with attitude and practice of premarital sex (p < 0.05,  2). The prevalence of premarital sex was comparable with recent domestic and regional data, yet implied an increased trend. Up to one-fifth of students were not equipped with enough knowledge of safe sex, therefore, reproductive and sexual health education for bedsit-living students should be reinforced.

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