OBJECTIVE: Prostate cancer can have significant physical, psychological, and social impact on patients, particularly early in the treatment course. While psychological intervention during oncologic care has been shown to improve all aspects of well-being, few studies have focused on men diagnosed with prostate cancer or have targeted the period between diagnosis and treatment. We evaluated the efficacy of an innovative, brief psychosocial counseling program delivered to men before and after prostate cancer treatment. METHODS: One hundred thirty-two men diagnosed with prostate cancer were randomly assigned to either intervention (n = 69) or control (n = 63) groups. Participants completed the Profile of Mood States (POMS), Index of Coping Responses (ICR), and scales measuring general and disease-specific HRQOL, at baseline (before treatment commenced) and at months 3 and 12. Both groups received standard medical care; and intervention participants received 2 sessions of counseling before treatment and one session 4 to 6 weeks after treatment completion. RESULTS: Intervention effects were evaluated using a mixed model analysis, adjusting for cancer treatment (radiation or surgery) and time. There were no significant differences between groups at baseline on the demographic or psychosocial measures. In the mixed model, intervention participants reported significant improvements over time on three outcomes: Vigor (POMS; p <0.05) and Information Seeking and Affective Regulation (ICR; p <0.01 and p <0.05, respectively). CONCLUSIONS: While the brief intervention did not appear to influence HRQOL, or prostate-specific symptoms, it improved energy level and coping responses, particularly those relevant to managing information and emotions. These coping strategies may be especially important given the decision-making and treatment initiation tasks of early prostate cancer care. Source of financial support: California Cancer Research Program Grant # 97-12013.