BACKGROUND: Among the number of reasons that expose the youth to reproductive health risks, lack of adequate information on sexual and reproductive health issues is of prior concern. Given the lack of readily available information about sexual activity to teens, they turn to media for information about sexual norms and may also use the media as a sexual super-peer that encourages them to be sexually active. Therefore, this study was aimed to assess the association between exposure to sexually explicit materials and sexually risky behaviors among undergraduate students of Ambo University, Ethiopia.  METHODS: Institutional based cross-sectional study was conducted among 403 university students in 2018. Study participants were selected by systematic random sampling technique. Self- administered questionnaire was used to collect data. Data were analyzed using SPSS statistical software version 20. Uni-variate, bivariate and multiple logistic regression analyses were done.  With 95% CI, the p-value of less than 0.05 was taken as the level of significance.RESULTS: About 55% and 52% of the university students were exposed to sexually explicit electronic materials throughout their life and in the last 12 months prior to data collection period respectively. Searching for sex information was the top reason for why university students resorted to watching sexually explicit materials. Sexually active students, senior students and male students were more likely to engage in watching sexually explicit electronic materials compared to their counterparts. CONCLUSION: A high numbers of university students were being exposed to sexually explicit electronic materials for the sake of searching about sexual and related information. This exposure has a significant association with risky sexual behaviors specifically. We highly recommend that university organize awareness creation forum on the area of sexual health, HIV/AIDS and STI, and related matters.KEYWORD: Sexually explicit materials, risky sexual behaviors, Ambo University