Many children with pervasive developmental disorders (PDD) exhibit behaviors and symptoms of attention-deficit/hyperactivity disorder (ADHD). We sought to determine the relative efficacy of medications for treating ADHD symptoms in children with PDD by identifying all double-blind, randomized, placebo-controlled trials examining the efficacy of medications for treating ADHD symptoms in children with PDD. We located seven trials involving 225 children. A random effects meta-analysis of four methylphenidate trials showed methylphenidate to be effective for treating ADHD symptoms in children with PDD (ES = 0.67). Several adverse events were greater for children were taking methylphenidate compared to placebo. An individual trial of clonidine and two trials of atomoxetine suggest these agents may also be effective in treating ADHD symptoms in children with PDD.