Aims: There are few data examining differences in renal structure between the sexes. Elucidation of the mechanisms responsible for the observed effects of sex on the progression of chronic renal disease requires knowledge of the effects of sex on renal structure. Results: Although we found that male kidneys weigh more than female kidneys, sex is not an independent determinant of kidney weight. The increased kidney weight seen in men is solely dependent on their greater body surface area. We found no difference in glomerular number between men and women. Although men had larger glomeruli than women, sex is not an independent determinant of glomerular volume. The occurrence of larger glomeruli in men is solely dependent on their greater body surface area. Similarly, the greater total glomerular volume seen in men as compared to women reflects increased kidney weight in men. Sex is not an independent determinant of total glomerular volume. Conclusions: These findings do not support the hypothesis that renal structural differences contribute to sex-related differences in the rate of progression of chronic renal disease.