Background The risky behaviors of youngsters or youths may further be worsened by the logic that university students are too many in number, lack facilities for sexual and reproductive health services and live away from their parents and free from parental control. To tackle the issue, evidence based intervention like improved access for youth’s friendly reproductive health services is crucial. In Ethiopia, despite the fact that much has been said about sexual and related issues of higher institution students, the assessment of the problem is not widely covered and search for solutions is mostly after the problem become deep-rooted. So, the purpose of this study was to assess the level of risky sexual behaviors among Wolkite University (one of the public higher institute) students. Methods A facility based cross-sectional study was employed using Cluster sampling to identify 1,123 students’ from each college, departments & sections of the colleges in the University, list of clusters (groups) was established with area of study and year of study. To select these clusters, list of cumulative frequencies of number of students was calculated. The total sample size was divided proportionately to the selected clusters and to both sexes (male and female). Accordingly, males and females were selected based on percentages calculated. Finally, a systematic sampling method was applied to select males and females from the cluster selected for the study after dividing the cluster in to male and female groups. Result In this emerging university ever use of substance reportedly was somewhat higher than a quarter, 28.7% (322) from a total of 1123 students. Among students reported ever use of substances, alcohol consumption was the predominant one, 157(14.0%), followed by khat, 57 (5.1%). Conclusion and recommendation The institute needs substantial progress in availing youth friendly reproductive health services as huge number of the youngsters, 225(20%) had risky sexual behavior and currently 7(1.5%) were HIV positive. Moreover, services for youths should be friendly and available with skillful professionals. This can be realized through the effort of tremendous stakeholders in the compound and elsewhere in the country like ministry of education/health or non-governmental organizations.