<ns4:p><ns4:bold>Background</ns4:bold></ns4:p><ns4:p> High-risk sexual behaviors(HRSBs) among young adults are key risk for Sexually Transmitted Infections(STIs), HIV and unplanned pregnancies. WHO has identified the 15-24years age-group as high-risk for STIs. Students at Higher Learning Institutions(HLIs) may be at higher risk because they are <ns4:italic>free</ns4:italic> of immediate parental-supervision, are a transient migratory population, probably at peak-years of sexual activity.  In Tanzania, information is limited on sexual and preventive behaviours among young adults in HLIs. We describe risky sexual behaviours and preventive practices among young adults attending HLIs in Mbeya-Tanzania.</ns4:p><ns4:p> <ns4:bold>Methods</ns4:bold></ns4:p><ns4:p> We conducted a cross-sectional study from March2019 to January2020 among randomly selected students aged 18-24years enrolled in HLIs within Mbeya.  Probability proportional to size was used to determine total student number from each HLI. We used a self-administered questionnaire to collect information on sexual health education, activity, behaviour and STI knowledge.</ns4:p><ns4:p> <ns4:bold>Results</ns4:bold></ns4:p><ns4:p> Total of 504students were enrolled with mean age of 21.5(SD 1.74)years. Total of 446(88.5%) students reported ever having had sex. Mean-age at first sex was 18.4years and 9.9% reported sexual debut <ns4:underline>&lt;</ns4:underline>15years. A higher proportion of male students(57%) reported sexual debut with non-steady partners than females(37.9%). Lack of condom use at sexual debut was reported by 52% of the participants. Consistent condom use during past 4-weeks was reported at 33% and 16.5% among males and females, respectively. About 1 in 10 students reported forced sex by someone they were dating. Sex under the influence of alcohol was reported by 24% of the students.  Nearly 8 in 10 (78.7%) students have heard of STIs, but only 16% were aware STIs can be asymptomatic. </ns4:p><ns4:p> </ns4:p><ns4:p> <ns4:bold>Conclusion</ns4:bold></ns4:p><ns4:p> STI prevention programs need to recognize young adults in HLIs as at-risk population; and advocate targeted messages to minimize risk to acquiring STIs, counseling and support for those experiencing sexual violence, promote condom use and safer-sex negotiation skills.</ns4:p>