The association of varicoceles with infertility is well established, but the exact effect of varicoceles on semen quality among patients with infertility is still poorly known. The study aimed to examine the prevalence of varicoceles among Chinese men with infertility and to examine the factors associated with semen quality.This was a cross-sectional study of 5447 male patients treated for infertility at the Affiliated Hospital of Guangdong Medical University from October 2012 to December 2015. The patients were divided on the basis of the presence of varicoceles. Examinations of the amount of semen and sperm morphology were performed according to seminal parameter detection methods recommended by the World Health Organization.Patients with varicoceles (n = 1429/5447, 26.2%) were slightly younger (P = .046), and had smaller testis (P = .019), higher frequency of abnormal epididymis (P < .001), slightly shorter infertility duration (P = .046), and lower frequency of smokers (P = .012). There was no difference in the distribution of occupations (P = .777). Using multiple linear regression analysis, varicoceles were shown to be independently associated with semen volume [B = −0.153, 95% confidence interval (95% CI): −0.245 to −0.062, P = .001], sperm concentration (B = 9.633, 95% CI: 7.152–12.114, P < .001), proportion of sperms with normal morphology (B = 0.951, 95% CI: 0.623–1.278, P < .001), motility (B = 3.835, 95% CI: 2.675, 4.995, P < .001), total sperm count (B = 22.481, 95% CI: 13.333–31.629, P < .001), and forward movement sperm count (B = 15.553, 95% CI: 9.777–21.329, P < .001). Varicoceles were present in 26% of Chinese male patients with infertility.Varicoceles were independently associated with sperm volume, sperm concentration, proportion of sperms with normal morphology, motility, total sperm count, and forward movement sperm count.