Introduction: The exact etiology of lower urinary tract symptoms caused by benign prostatic hyperplasia (BPH) has not yet been determined, and the etiology of erectile dysfunction (ED) is often multicausal and includes organic and/or psychogenic causes, as well as their combinations. Although the relation of BPH, and thus the volume of the prostate (VP) with ED is indisputable, precise mechanisms of integration are still under examination. Goal: The objective was to evaluate the correlation between prostate volume and degree of erectile dysfunction in patients with symptoms of lower urinary tract caused by benign prostatic hyperplasia. Material and Methods. 150 subjects with BPH, and before starting the BPH treatment, which can affect the sexual function, were divided into three groups: 50 patients with prostate volume of 30 to 40 ml (group A), 50 patients with a volume of 40 to 60 ml (group B) and 50 patients with prostate volume above 60 ml (group C). Quantification of erectile function is performed in all respondents by International Index of Erectile Function with five questions (IIEF-5). Results: The mean IIEF-5 in group A was 20.52 points with a standard deviation of 3.22, in group B 17.08 points with a standard deviation of 4.10, while in group C 10.78 points, with a standard deviation of 3.29. Comparing the results of a statistical analysis from all three groups of patients with the degree of ED, Group A had the highest value of IIEF-5, group C the lowest mean value of IIEF-5. The results of ANOVA (F=96.375, p=0.000) indicated that there was a statistically significant difference (p