IntroductionLow testosterone (T) has been suggested as a risk factor for Peyronie's disease (PD) that may correlate with disease severity. Low T is common in men with sexual dysfunction but its role in the pathogenesis of PD remains unclear. AimThe aim of this study was to compare the prevalence of low T (0.05). Of PD men, 52.9% had low T, compared with 45.9% of men with ED (P=0.35). T levels did not correlate with plaque size or degree of curvature in the PD group (P>0.05). ConclusionsMen with sexual dysfunction characterized by either PD or ED had similarly low T levels, and low T did not correlate with PD severity or surgical correction rate. The comparable prevalence of low T in men with PD or ED suggests the high rate of low T in PD men may be related to a common process among men with abnormal erectile physiology and not specifically causative in plaque formation. Kirby EW, Verges D, Matthews J, Carson CC, and Coward RM. Low testosterone has a similar prevalence among men with sexual dysfunction due to either Peyronie's disease or erectile dysfunction and does not correlate with Peyronie's disease severity. J Sex Med 2015;12:690-696.