Prior to scheduled surgery, breast cancer surgical patients frequently experience high levels of distress and expect a variety of post-surgery symptoms. Previous literature has supported the view that pre-surgery distress and response expectancies are predictive of post-surgery outcomes. However, the contributions of distress and response expectancies to post-surgical side effect outcomes have rarely been examined together within the same study. Furthermore, studies on the effects of response expectancies in the surgical setting have typically focused on the immediate post-surgical setting rather than the longer term. The purpose of the present study was to test the contribution of pre-surgery distress and response expectancies to common post-surgery side effects (pain, nausea, fatigue). Female patients (n=101) undergoing breast cancer surgery were recruited to a prospective study. Results indicated that pre-surgery distress uniquely contributed to patients' post-surgery pain severity (P<0.05) and fatigue (P<0.003) one week following surgery. Response expectancies uniquely contributed to pain severity (P<0.001), nausea (P<0.012) and fatigue (P<0.010) one week following surgery. Sobel tests indicated that response expectancies partially mediated the effects of distress on pain severity (P<0.03) and fatigue (P<0.03). Response expectancies also mediated the effects of age on pain severity, nausea and fatigue. Results highlight the contribution of pre-surgery psychological factors to post-surgery side effects, the importance of including both emotional and cognitive factors within studies as predictors of postsurgery side effects, and suggest pre-surgical clinical targets for improving patients' postoperative experiences of side effects.