Background: Patients may remain dissatisfied after penile prosthesis implantation for the treatment of erectile dysfunction. Studies showing the results of standardized protocols for preoperative psychological evaluation are lacking. Purpose: To estimate the rate of patients considered psychologically unfit for penile prosthesis implantation and to compare their characteristics with those considered fit after the implementation of a standardized psychological profile evaluation protocol for men with erectile dysfunction. Methods: Cross-sectional evaluation of men referred for penile prosthesis implantation by their urologists, based on organic causes for the erectile dysfunction, including a semi-structured (sexual and relational anamnesis of the patient and their partner, information about expectations about the results of the penile prosthesis implantation and possible complications) and a structured instrument including validated tools for the evaluation of depression and/or anxiety symptoms. These were the Self Reporting Questionnaire (SRQ-20), the 36-Item Short-Form Health Survey for quality of life, and the Five-Factor Model (FFM) for behavioral tendencies. After at least 3 interviews, the psychology team rated the patients as fit or unfit for surgery. Unfit patients were those with any of a set of warning signals indicating risk for dissatisfaction even after penile implantation. Main outcome measure: The prevalence of patients considered "unfit for surgery." Results: The quality of life scores were good, but 27.6% of patients (95% confidence interval, CI: 16.7e40.9%) were unfit for surgery. Being unfit was associated with obesity (P ¼ .027), anxiety and/or depression symptoms (P < .001) and high levels of neuroticism (P ¼ .001). Conclusion: The preoperative evaluation protocol combining standardized and validated tools shows that more than one-quarter of patients with a medical indication for penile prosthesis implantation were not in good psychological conditions for the surgery. The development of psychological evaluation protocols can help identify patients in need of adequate care before penile implantation. M de Mello Ferreira dos Reis, EA Corrêa Barros, M Pollone, et al. Preoperative Psychological Evaluation for Patients Referred for Penile Prosthesis Implantation. Sex Med 2020; XX:XXXeXXX.