Obsessive-compulsive disorder (OCD) is ranked by the World Health Organization (WHO) among the 10 most debilitating disorders. The treatments which have been found effective are cognitive behavior therapy (CBT) and serotonin reuptake inhibitors (SRI). This meta-analysis includes all RCTs of CBT (25) and SRI (9) for OCD in youth using the Children's Yale-Brown Obsessive Compulsive Scale (C-YBOCS). CBT yielded significantly lower attrition (12.7%) than SRI (23.5%) and placebo (24.7%). The effect sizes for comparisons of CBT with waiting-list (1.53), placebo (0.93), and SRI with placebo (0.51) were significant, whereas CBT vs. SRI (0.22) and Combo (CBT+SRI) vs. CBT (0.14) were not. Regarding response rate CBT (70%) and Combo (66%) were significantly higher than SRI (49%), which was higher than placebo (29%) and WLC (13%). As for remission CBT (53%) and Combo (49%) were significantly higher than SRI (24%), placebo (15%), and WLC (10%), which did not differ from each other. Combo was not more effective than CBT alone irrespective of initial severity of the samples. The randomized controlled trials (RCTs) have a number of methodological problems and recommendations for improving research methodology are discussed as well as clinical implications of the findings. Keywords: Children; Cognitive therapy; Exposure and response prevention; Meta-analysis; Obsessive-compulsive disorder; Systematic review.