A major goal of science education reform is to produce curricula that improve the learning of all students. In this study, the authors explore the use of design-based learning (DBL) to achieve this end. They examined two middle school science classes taught by a teacher who switched for the first time from a standard, scripted inquiry approach to a DBL approach. The researchers were particularly interested in two questions. First, will students previously labeled high and low-achievers become equally engaged by DBL? Second, will the traditional gaps in science achievement associated with race/ethnicity, gender, and socio-economic status be increased or reduced? The findings presented two aspects of learning: engagement and achievement. Engagement has the potential to highlight students' performance in a way that standardized assessment methods do not reveal. The findings of this study suggest that DBL has the potential to increase students' desire to learn, enhance students' success in science class, and increase students' interest in science topics. (Contains 2 tables and 3 figures.)