The authors tested effects of a 10-week group cognitive-behavioral stress management intervention among 100 women newly treated for Stage 0-II breast cancer. The intervention reduced prevalence of moderate depression (which remained relatively stable in the control condition) but did not affect other measures of emotional distress. The intervention also increased participants' reports that having breast cancer had made positive contributions to their lives, and it increased generalized optimism. Both remained significantly elevated at a 3-month follow-up of the intervention. Further analysis revealed that the intervention had its greatest impact on these 2 variables among women who were lowest in optimism at baseline. Discussion centers on the importance of examining positive responses to traumatic events--growth, appreciation of life, shift in priorities, and positive affect-as well as negative responses.