The accuracy of predictions of how people will react to a medical test result is important because it may influence the decision to be tested. We hypothesized that people would overpredict their own long-term reactions to HIV test results (i.e., that they would feel better in response to seropositive results and worse in response to negative results than they expected to). In the first study phase, anticipations of reactions to positive and negative HIV test results were obtained from 50 subjects. In the second phase, postresult reactions were obtained about 5 weeks after subjects learned the results of their tests. The results suggest that people anticipate more distress given a positive result and anticipate less distress given a negative result than they experience. Cautions about the comparability of the 2 samples and recommendations for further research are discussed.