Introduction: Sexual functionality, a critical component of health-related quality of life, can decline for various reasons, including heart failure (HF). Our purpose was to prospectively evaluate male patients with HF scheduled for cardiac resynchronization therapy (CRT) in terms of sexual function, erectile function, and alterations in hormonal and biochemical parameters. In addition, we sought to determine the sexual functioning of the partners of these patients.Methods: The study enrolled 103 male patients and their partners. The International Index of Erectile Function-5 (IIEF-5) was administered to all males and the Arizona Sexual Experience Scale (ASEX) questionnaire was completed by all participants, at baseline and three months after CRT.Results: The ASEX scores of patients and partners demonstrated significant declines from baseline to post-intervention analysis. The IIEF-5 scores of patients showed a significant increase from baseline to post-intervention (p=0.001 for all).Conclusion: We conclude that sexual dysfunction is experienced by the partners of male patients with erectile dysfunction before CRT and that reversal of erectile problems with CRT yields improvements in both male and female sexual functions.