Purpose Men affected by multiple sclerosis often experience neurogenic overactive bladder (OAB), lower urinary tract symptoms and erectile dysfunction (ED). The aim of the study was to investigate modifications of urinary and sexual functions after administration of daily tadalafil (TAD) 5 mg. Methods Twenty men were enrolled in a single- blind, 4- week prospective study while 10 men without treatment served as controls. Primary outcomes were changes from baseline of International Prostate Symptom (IPSS), OAB questionnaire (OAB- q- short form) and International Index of Erectile Function (IIEF- 5) scores. To evaluate the influence of bladder filling on somatic reflexes, we studied variations of the H- reflex evoked by electrical stimuli applied to the tibial nerve at the popliteal fossa and recorded from the soleus muscle. Also testosterone/ estradiol (T/ E) ratio was measured before and after treatment. Results In TAD group, an improvement in IPSS (p < 0.001), OAB- q (p < 0.001) and IIEF- 5 ( p < 0.001) scores was found. Also, an increase in Qmax (p < 0.01) and T/ E ratio (p <0.01) was found with a concomitant reduction in post- void residual volume (p <0.001) without any changes in the H- reflex. Conclusions The study demonstrates for the first time that daily TAD in patients with multiple sclerosis improves storage symptoms, post- void residual volume, steroid hormone pattern and ED without urodynamic changes.