Recently, conceptual change research has been experiencing a warming trend (G. M. Sinatra, 2005) whereby motivational and affective factors are being explored in the conceptual change process. The purpose of this study is to explore the 2 × 2 framework of achievement goal theory in relation to students' conceptual change learning for a specific topic in biology, HIV/AIDS. The authors hypothesized that those with approach goals (mastery approach and performance approach) would demonstrate greater posttest conceptual change in their understanding of HIV/AIDS than those with avoidance goals. Participants were 206 undergraduates in introductory-level college biology courses. Participants were provided a 1,004-word HIV/AIDS text and were pre- and posttested on their conceptual knowledge of HIV/AIDS. Results of an analysis of covariance indicated that approach-oriented students demonstrated greater conceptual HIV/AIDS change at posttest than avoidance-oriented students. Results are discussed in light of the warming trend and achievement goal theory.