Introduction: The International Index of Erectile Function (IIEF) was developed to address the need for a self-report measure of both erectile function and sexual function that can be given under the guidance of a clinician. Aim of the work: to translate the international index of erectile function (IIEF-15) and to adapt an Arabic version of the (IIEF-15), then to test its validity and reliability of among Egyptian population. Patient and Method: the study included two groups, 77 erectile dysfunction patients who are about to start the intracavernosal injection home therapy program and another 77 subjects with no history of erectile dysfunction as a control group, patients and controls both completed the translated and adapted (the international index of erectile function -15) at base line (just before treatment for the patients) and after four weeks, the questionnaire was self- administered by all, with guided assistance available when needed.Reliability and validity was assessed by calculating Cronbach’s alpha (internal consistency), intraclass correlation coefficient (test-retest repeatability).Discriminant validity was demonstrated by comparison of baseline mean scores between patients and controls. Effect size was evaluated to assess the sensitivity to change.Sensitivity was assessed by comparing the mean pretreatment and post-treatment item and domain scores of the patients.Specificity was assessed by comparing the mean baseline and end-point item and domain scores of the controls.Results: Internal consistency was good. A high degree of internal consistency was observed for each of the 15 items and five domains (Cronbach’s alpha value 0.76 and higher and, 0.77and higher, respectively).Intraclass correlation coefficient for15 items and domains were high (Intraclass correlation coefficient 0.62 and higher and, 0.77and higher, respectively).The IIEF does discriminate between subjects with and without erectile dysfunction (significant differences were observed between mean scores of the patients and the controls) (P value less than 0.05) indicating adequate discriminant validity.High values of effect size index (Cohen's d) indicate that the questionnaire has an excellent sensitivity to change.Also it turned to be of high specificity( differences between mean scores of the control group at baseline and at end point after four weeks did not approach significance)(P value is higher than0.05) and sensitivity (significant differences were observed between mean scores of the pretreatment and thepost treatment questionnaire administration)(P value less than 0.05) which indicates that changes in IIEF-15 scores reflect meaningful detection of erectile dysfunction.Conclusion: It can be concluded that the Arabic version of the IIEF-15 is suitable, reliable, valid, specific and sensitive to clinical change in the Egyptian population.