Background: The use of khat among youths can be harmful leading to decreased academic performance, increased risk of contracting HIV and other sexually transmitted diseases or other psychiatric disorders such as lethargy, hopelessness and insomnia. It is believed to be one of the factors associated with unprotected risky sexual behavior predisposing the youth for HIV infection and transmission. Methods: Health institution based cross-sectional study was conducted in South West Ethiopia from January 15 – March 20, 2012. A sample size of 410 was calculated by Epi-info stat calc and stratified sampling technique was used. Multivariate logistic regression and Cox regression was used to assess the degree of association between dependent and independent variables.Result: Khat use was positively associated with being male[OR & (95%CI) = 2.89 (1.39, 5.93)], alcohol use[OR & (95%CI) = 4.75 (2.12, 10.63)], not having comprehensive knowledge on HIV[OR & (95%CI) = 2.33 (1.20, 4.53)], viewing sexual films[OR & (95%CI) = 2.08 (1.01, 4.26)] and not
having communication with parents about khat chewing[OR & (95%CI) = 2.93 (1.33, 6.47)]. Initiation khat use before 18
years was also positively associated with not having comprehensive knowledge on HIV[Adj. HR & (95%CI) = 1.57 (1.09,
2.55)], alcohol use[Adj. HR & (95%CI) = 3.33 (1.65, 6.74)] and watching sexual films[Adj. HR & (95%CI) = 1.85(1.03,
3.30)].Conclusion: Measures such as educational campaigns need to be instituted to create awareness among youths and
their parents in order to reduce the prevalence of khat chewing habit and its adverse social and health consequences