Sickle cell disease is known to cause glomerulopathy, including focal segmental glomerulosclerosis (FSGS). Patients who have sickle cell glomerulopathy with FSGS are thought to have a poorer prognosis than patients who have sickle cell glomerulopathy without this lesion. The former patients are more likely to have persistent proteinuria and eventually develop end-stage renal disease. We present a boy with sickle cell glomerulopathy and FSGS who is younger than patients with similar findings reported previously. The histopathology of his renal lesions is remarkable for segmental ultrastructural changes in the glomerular basement membranes and endothelial cells. We speculate that these changes are precursory to the pathogenesis of glomerular sclerosis in patients with sickle cell disease.