Introduction Testosterone deficiency syndrome (TDS) is usually suspected on the basis of signs/symptoms. However, some men with low testosterone levels (low T) are asymptomatic or present mild, unnoticed symptoms. Would they have the same cardiovascular risk as symptomatic men? Aims This study aims to assess the relationship between presence/severity of low T-related symptoms and the likelihood of metabolic syndrome (MetS). Methods Data were taken from a multicenter, cross-sectional study conducted in Spain among men visiting men's healthcare offices aged 45 with low T (total T <8nmol/L or <12nmol/L and calculated free T <250nmol/L). Only subjects whose MetS components and symptoms had been assessed were selected. Data available included anthropometrics, toxic habits, comorbidities, and total testosterone (TT) levels. Main Outcome Measures MetS was defined using the harmonized definition. Erectile dysfunction was classified using the International Index of Erectile Function questionnaire. The Ageing Male Symptoms (AMS) scale assessed symptoms. Symptom severity was classified as none/mild and moderate/severe. Bivariate and multivariate logistic regression analyses were performed to calculate the effect of moderate/severe symptoms on the odds ratio (OR) for MetS. Results Mean age (SD) was 61.2 (8.1) years. Erectile dysfunction (ED), AMS, and MetS prevalence were 97.4%, 94.9%, and 69.6%. Prevalence of MetS was higher in men with moderate/severe symptoms vs. men with no/mild ones (75.3% vs. 57.9%, P<0.001). Age and prevalence of TT <8nmol/L, moderate/severe ED, and obesity were significantly higher in men with moderate/severe symptoms. Multivariate analysis showed that besides obesity and moderate/severe ED, moderate/severe symptoms increased the likelihood of MetS. This effect disappeared in men with severe ED and in the nonobese. Three symptoms showed relationship with MetS after adjusting for all confounding factors. Conclusion Severity of TDS symptoms may indicate higher cardiovascular risk in men with low T. Garcia-Cruz E, Leibar-Tamayo A, Romero-Otero J, Asiain I, Carrion A, Castaneda R, Mateu L, Luque P, Cardenosa O, and Alcaraz A. Marked testosterone deficiency-related symptoms may be associated to higher metabolic risk in men with low testosterone levels. J Sex Med 2014;11:2292-2301.