AbstractA method of measurement of glomerular cross‐sectional area was applied to 267 renal biopsies from 19 groups of patients with well‐defined pathological and clinical conditions. There was a correlation between the mean glomerular area for each group and the percentage of global sclerosis in each group. A few groups had glomeruli that were larger than would be expected from their percentage of global sclerosis, probably due to cellular proliferation and/or infiltration. A few groups had glomeruli that were smaller than would be expected from their percentage of global sclerosis, probably due to ischaemic shrinkage. These observations indicate that as well as the known influence of body size on the glomerular area, the number of functioning glomeruli in the body has an important effect on the glomerular area.