Women with breast cancer express the greatest need for counseling at the time of diagnosis and report that the intervention they want is to be able to speak with someone who has the same cancer, but has lived through the crisis of treatment and is leading a ‘normal’ life. We conducted an observational study of a 6-month peer-counseling intervention testing outcomes for both newly diagnosed women (Sojourners) and peer counselors (Navigators) as a first step toward the goal of validating a peer navigator program. Significant improvement in the Sojourners was observed in trauma symptoms, emotional well-being, cancer self-efficacy, and desire for information on breast cancer resources. Navigators maintained baseline levels of the outcome variables, but increased in dissatisfaction with their interactions with their medical team and increased emotional suppression. Our findings indicate that peer navigation may halt a decline in quality of life that is commonly found in the first year following breast cancer diagnosis. In addition, Navigators were not adversely affected by their experience; however, careful training and supervision of Navigators is crucial to overall success. Randomized clinical trials are needed to demonstrate the efficacy of peer navigator programs. Copyright © 2006 John Wiley & Sons, Ltd.