Background: In spite of antiemetics, postchemotherapy side effects continue to be common and may affect compliance to cancer treatment. Among the known factors associated with increased symptom severity are: younger age, treatment toxicity, expected severity, and distress, but little is still known about the role of other factors. The aim of our study was to investigate the role of individual differences related to sensory perception for posttreatment side effects. Methods: Hundred and twenty-five women receiving adjuvant chemotherapy for breast cancer completed measures of absorption, autonomic perception, somatosensory amplification, trait anxiety, and expected severity at baseline. Pretreatment distress and posttreatment nausea, vomiting, and fatigue were assessed at the 1st, 4th, 6th and last cycles of chemotherapy. Results: While univariate analyses showed several factors to be associated with side effects, only absorption and pretreatment distress remained independent predictors of nausea and fatigue when controlling for the remaining factors. Posttreatment vomiting was only predicted by expected severity of vomiting. Conclusion: Chemotherapy-induced side effects are related to increased autonomic nervous system activity, and absorption has been associated with increased autonomic nervous system reactivity to stress. The results suggest that individuals with high absorption may be at greater risk for developing side effects. Improved precision in identifying patients at risk of experiencing more severe side effects after cancer treatment will increase the ability to target treatments aimed at reducing these side effects.