Ultrastructural glomerular basement membrane changes are present in most hereditary glomerular diseases: thick and thin basement membrane with splitting of the lamina densa in Alport’s syndrome, thin basement membrane in familial benign essential hematuria, and thick basement membrane with the presence of collagen-like fibrils in the nail-patella syndrome. They are useful markers for diagnosis. Moreover, their knowledge has set the problem of the primary biochemical defect in basement membrane metabolism accounting for morphological abnormalities and clinical disturbances. Further biochemical and immunochemical investigations are still required for a better understanding of hereditary glomerular diseases.