To design effective solution for the problem substance abuse, it is essential to understand its predictors and assess its prevalence, even though the prevalence is thought to be increasing; only little is known in any Ethiopian setting. The study revealed 47.6 % life time prevalence and 40.6 % current prevalence of substance use specifically 31.1 % Khat Chewers, 14.1 % Alcohol drinkers and 6.7 % cigarette smokers. Using logistic regression, male gender (p<0.001), being in the age group 19-29 (p=0.001), having substance user family (p=0.04), and having substance user friend (p<0.001) were...