Background: Sexually explicit media (SEM) are textual, visual, or aural materials thatrndepict sexual acts or expose the reproductive organs of the human body. These erotic andrnpornographic materials usually portray sex in a risk free manner. Exposure of urbanrnyouth to such media is argued to contribute for adoption of risky sexual behavior.rnObjective: This study aimed to assess magnitude of exposure to SEM and factorsrncontributing to exposure among in-school youth as well as describe sexual behavior andrnthe role of exposure and other factors as predictors of in-school youth sexual activity.rnMethodology: A cross-sectional descriptive study involving 810 randomly selectedrnstudents among 18 Addis Ababa high schools was conducted in March 2008. Pre-testedrnquestionnaire was used to collect quantitative data, which was entered and cleaned usingrnEPI INFO 2000 version 3.3 and analyzed using SPSS version 13.0 statistical packages.rnOdds Ratio with 95% Confidence Interval was used and multiple logistic regressionrnanalysis was performed to assess association among variables. Tape-recorded qualitativerndata, from four FGDs were transcribed and analyzed into predetermined themes.rnResults: Magnitude of ever-exposure to sexually explicit texts and watching movies werern65.3% and 69.5% respectively. The odds of frequent exposure to SE movies increasedrnwith being male, consuming alcohol and Khat, having positive attitude towards SEM, andrnsexual experience while the later two and school type affected frequency of reading SErntexts. Nearly eighteen percent of the participants were sexually active. Likelihood ofrnviirnbeing sexually active grew with frequent reading of SE texts with AOR of 3.69 (95%C.I.rn=1.17, 11.63), frequent viewing of SE movies, AOR 7.68 (95%C.I. =2.74, 21.57), alcoholrndrinking, AOR 3.77 (95%C.I. =1.54, 9.21), Khat chewing AOR 4.10 (95%C.I. =1.36,rn12.32), and ever having a boy or girl friend AOR 3.43, (95%C.I. =1.65, 7.12). Probabilityrnof sexual engagement decreased among those who live with their parents AORrn0.20(95%C.I. =0.04, 0.88). Recalled attendance of school sex education by 56.5%rnshowed no significant association. Inconsistent condom use by 60.9% and havingrnmultiple sexual partners by 57% of the sexually active youth were also reported.rnConclusion and recommendation: A strong link was revealed between frequentrnexposure to sexually explicit materials, alcohol and Khat consumption, and sexualrnactivity of the in-school youth. Large proportions of sexually active youth are alsornengaged in risk sexual behavior. Considering these, developing media criticizing skill ofrnstudents, decreasing accessibility to SEM through legal measures, promotion of peer andrnschool sex education and encouraging parental guidance were some of thernrecommendations forwarded.