This article describes two studies testing the efficacy of a commercial one-on-one cognitive training program (LearningRx) and its computer-based version (Brainskills) in laboratory and school settings. Study 1 tested Brainskills in a laboratory setting with 322 middle school students. Paired "t"-tests revealed significant gains on all cognitive measures and math performance after 3 weeks of training. Study 2, a randomized control study, included 225 high school students randomly assigned to one of three conditions: LearningRx, Brainskills, or study hall (control) in a school setting for a 15-week training period. Univariate ANCOVAs revealed significantly higher scores for the treatment groups compared with controls on working memory, logic and reasoning, and three of four math attitude measures but not for math performance. Implications for school-based interventions are discussed.