Abstract Introduction Erectile dysfunction (ED) is the most frequent male sexual dysfunction along with premature ejaculation. Moreover, its prevalence is increasing worldwide due to ageing of the population and spreading of risk factors like obesity, diabetes, hypercholesterolemia, hypertension, etc. Also, it represents an important cardiovascular risk marker because of its demonstrated tight association with cardiovascular disease (CVD). We dispose of many diagnostic tools to assess ED and a proper workup includes the anamnesis, a physical exploration, blood tests for hormonal and metabolic evaluation, and ED grading through validated questionnaires such as the International Index of Erectile Function (IIEF). One of the instrumental tests we may indicate is the nocturnal penile tumescence (NPT) test or “Rigiscan”. This test measures the spontaneous erections overnight and helps discriminating between organic and psychological ED. However, this is a highly specific but low sensitive test since a positive (normal) result can roll out an organic ED and suggest a psychological etiology while a negative result cannot confirm or exclude an organic condition. Objectives In this context the aim of this study is to investigate the predictive role of Rigiscan in discriminating patients with an organic ED and the presence of vascular disease in patients with ED. Methods We conducted a prospective study in patient 25 patient who underwent a Rigiscan test as part of ED assessment. Each patient had blood tests for hormonal and metabolic analysis, a measurement of the carotid intima-media thickness (cIMT), a brachial flow-mediated vasodilation test (FMD), and a penile color doppler ultrasound (PCDU) to assess penile hemodynamics. Results Our patients had a mean age of 47.9 ± 13.7 years, with a mean IIEF score of 9.0 ± 6.5. Among them 13 (54.2%) were active smokers, 5 (20.8%) were diabetics, 8 (32%) had dyslipidemia, and 4 (16.7%) had hypertension. Eleven patients (44%) had a normal Rigiscan while 14(56%) had a pathological result. We found that patient with a pathological Rigiscan presented with a cluster of impaired vascular function at different levels. In particular, they had statistically lower peak systolic velocity (PSV) in the PCDU (52.5 vs 80.2 cm/s p=0.014) and a higher prevalence of arterial insufficiency (42.9% vs 0.0% p=0.020). Moreover, in patients with negative Rigiscan, there was a higher cIMT (0.9 vs 0.7 mm) and lower response to FMD (7.7% vs 9.6%) with a more frequent diagnose of impaired FMD (63.6% vs 46.2%) but without reaching a statistically significance. Conclusion We can conclude that a negative Rigiscan is indicative of altered penile hemodynamics and may suggests the presence of systemic vascular disease. Therefore, while a positive Rigiscan excludes organic ED, a negative Rigiscan should be considered a cardiovascular risk marker and induce the clinician to address the cardiovascular risk in that patient. More studies with larger population are warranted to confirm and further investigated these findings. Disclosure No