The aim of this study was to investigate the role of systemic inflammation by means of the neutrophil-to-lymphocyte ratio (NLR) in men with erectile dysfunction (ED). Complete demographic, clinical, and laboratory data from 279 consecutive men with newly diagnosed ED were analyzed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). A complete blood count was requested for every man, and the NLR was calculated for every individual. Patients were invited to complete the IIEF questionnaire. Logistic regression models tested the odds (OR, 95% CI) of severe ED (defined as IIEF-EF 0), metabolic syndrome, NLR, cigarette smoking, and color duplex Doppler ultrasound parameters. Likewise, LNR values were also dichotomized according to the most informative cutoff predicting severe ED using the minimum p value approach. Median [IQR] age of included men was 51 [40-64] years. Of all, 87 (31%) men had severe ED. Men with severe ED were older (median [IQR] age: 61 [47-67] vs. 49 [39-58] years) and had a higher rate of CCI>0 [46/87 (53%) vs. 44/192 (23%) patients]. Thereof, NLR was dichotomized according to the most informative cutoff (NLR>3); patients with severe ED more frequently had NLR>3 as compared to all other ED patients [namely, 18/87 (21%) vs. 13/192 (7%)]. At multivariable logistic regression analysis, NLR>3.0 emerged as an independent predictor (OR [CI] 2.43 [1.06; 5.63]) of severe ED, after accounting for other clinical variables. A NLR>3 increased the risk of having severe ED in our cohort, boosting the already existing evidence linking systemic inflammation to ED. Moreover, this easily obtainable index can be clinically useful in better risk-stratifying patients with ED. © 2018 American Society of Andrology and European Academy of Andrology.