Research on neuropsychological difficulties among cancer patients has focused on chemotherapy as a primary cause, yet several studies have now shown that some patients evidence cognitive weaknesses prior to chemotherapy. As an alternative to the 'chemo-brain' theory, this study examined the hypothesis that stress and coping style may be associated with observed neuropsychological difficulties among female cancer patients. Thirty-six women completed neuropsychological testing and psychological questionnaires following surgery for breast cancer and prior to any subsequent treatments. Twenty-seven percent of participants evidenced deficits on at least one measure of verbal fluency, and 14% of participants were impaired on at least one memory measure. Self-reported stress was correlated with deficits in memory, verbal fluency, and attention. Subsequent mediational analyses indicated that use of passive coping styles may underlie this relationship between stress and neuropsychological deficits. These findings highlight the potential relevance of psychological mechanisms, such as coping style, in cancer patients' experience of neuropsychological deficits.