Factors related to the prevalence, prediction, and course of anticipatory nausea (AN) in women (n = 77) receiving adjuvant chemotherapy for breast cancer were examined. Using a prospective longitudinal research design, patients were interviewed both before and after each chemotherapy infusion. Fifty-seven percent of the patients developed AN. These patients were characterized by more severe gastrointestinal side effects following the initial infusion and greater expectations for experiencing chemotherapy-related nausea. A more rapid development of AN was related to a history of experiencing nausea across a greater variety of situations, higher IV drug doses, and less infusion-related anxiety at the initial infusion. Although AN occurred intermittently across treatment sessions, severity was constant. Results provided strong support for the hypothesis that classical conditioning processes are instrumental in AN acquisition. The role of anxiety in the development of AN is considered as are clinical implications for the prevention of AN and recommendations for future research.