Purpose: Fear of cancer recurrence (FCR) is a significant source of distress in men with prostate cancer and could affect clinical decision-making, especially in those with positive margins following radical prostatectomy (RP). We examined the influence of positive surgical margin status on fear of cancer recurrence in men undergoing radical prostatectomy. Methods: Five hundred eight-four men underwent RP from 1999 to 2002 in CaPSURE™, a prospective, longitudinal, national cohort. All men had both baseline and follow-up assessment of FCR using a validated Kornblith scale. Statistical analysis included χ2 test, Wald test, and linear as well as repeated measures ANOVA mixed model. Results: One hundred sixty (27%) men had positive surgical margins. Baseline FCR and clinical variables did not differ based on margin status. Men with positive margins experienced greater FCR after RP than negative margins (OR, 1.94, 95% CI, 1.22-3.07). Men who had received adjuvant therapy experienced greater FCR (OR, 2.78, 95% CI, 1.21-6.39). Repeated measures analysis showed greater FCR over time (14-month mean follow-up, range 2-31 months) for positive vs. negative margins (P = 0.02). This difference in fear widened over time. There were no significant differences in health-related quality of life scores based on margin status. Conclusion: Positive surgical margin status is associated with greater fear of cancer recurrence, a difference not alleviated by adjuvant therapy use. Men with positive margins remain more fearful over the course of several years compared with those with negative margins. Clinicians should be aware of the potential stressful impact of positive surgical margins. © 2010 Elsevier Inc.