Objective-Treatment for localized carcinoma of the prostate (PCa) is frequently associated with decrements in sexual functioning and satisfaction. Given the highly interpersonal nature of these decrements, interpersonal problems (such as interpersonal sensitivity) may affect recovery of sexual functioning after PCa treatment by interfering with physician and partner communication and through distorted cognitions surrounding sexual dysfunction. The objective of the present study was to determine the effect of interpersonal sensitivity on several treatment indicators, including response to a group based psychosocial intervention.Methods-Participants were 101 older men recovering from radical prostatectomy and were enrolled in a randomized controlled trial of a 10-wk group-based cognitive behavioral stress management (CBSM) intervention. Measures included the Inventory of Interpersonal Problems (IIP) and the Sexual Functioning subscale of the UCLA quality of life measure.Results-At baseline, interpersonal sensitivity was related to a belief linking sexual dysfunction to core male identity (r = .29, p < .05). Using hierarchical regression, we found that (a) the CBSM intervention was effective in promoting sexual recovery in all participants and that (b) this effect was moderated by interpersonal sensitivity, such that individuals with higher levels of interpersonal sensitivity made larger improvements in sexual functioning in response to CBSM.Conclusions-CBSM was effective for improving sexual function after radical prostatectomy. Individuals with higher levels of interpersonal sensitivity were more likely to perceive sexual dysfunction as a threat to masculine identity and made larger gains in the CBSM intervention. Results and relevance to the older male cancer patient are discussed from the perspective of interpersonal theory.