Two experiments investigated baseline reviews as a relevant variable in reorganization of equivalence classes. After formation of three 4-member classes, participants learned reversals of baseline conditional discriminations and expanded the classes to 5 members each. In Experiment 1, 4 students responded on equivalence probes without baseline reviews preceding each test. They seldom reorganized classes consistently with reversed baselines. Their performance was sometimes consistent with the original baseline and sometimes inconsistent with both baselines. In Experiment 2, 4 additional students received the same training and tests, with baseline reviews preceding each test. These participants always reorganized classes consistently with the reversed baselines. Baseline reviews may have functioned as contextual cues, strengthening the most recent baseline against the conflicting earlier ones. (Contains 4 tables and 1 figure.)