Determinations of plasma levels of sexual hormones in 43 male patients of chronic renal failure showed that the content of testosterone (T) decreased markedly, while estradiol (E2) and E2/T ratio were obviously higher than in normal subjects, with no significant correlation between the levels of these sexual hormones and renal function. According to syndrome-differentiation of TCM, 17 of the 43 cases belonged to deficiency of Kidney-yang, and the other 26 cases deficiency of Kidney-yin. In the patients with deficiency of Kidney-yang, the E2 level was not increased, but the T content decreased to make the E2/T ratio apparently elevated; whereas in the patients with deficiency of Kidney-yin, both E2 and E2/T were elevated. The level of E2 in deficiency of Kidney-yin was markedly higher than that in deficiency of Kidney-yang. The results indicated that patients of chronic renal failure of the type of deficiency of Kidney-yang differed in syndrome as well as in levels of the sexual hormones from the type of deficiency of Kidney-yin; however, the sexual hormones were not correlated with the renal functions in the two types of patients.