In 23 cases of perimembranous glomerulonephritis (PGN, membranous nephropathy), the juxtaglomerular cell complex (JGC‐complex) in early postmortal (2 cases) and bioptically obtained specimens (21 cases) was investigated quantitatively by planimetry. The results were correlated with the stage of the PGN and the clinical findings. A statistically significant increase in mean size of the JGC‐complex was found in perimembranous glomerulonephritis compared with the control group (p < 0.005). Comparing the different morphological stages of PGN, the size of the JGC‐complex was increased and the serum creatinine level raised in stages 3 and 4. In hypertensive patients with perimembranous glomerulonephritis, the serum creatinine levels were significantly raised as compared with the normotensive group.