Six children with membranoproliferative glomerulonephritis Type II (MPGN II-dense deposit disease), who were followed an average of 14 years (3.5 to 22 years) and treated continuously with an alternate-day prednisone regimen, have been studied by successive renal biopsies over intervals of 2 to 14 years of disease. All have shown significant reduction in mesangial proliferation and improvement of capillary lumen patency. A change in position of the deposits, from the lamina densa to the lamina rara interna, was demonstrated ultrastructurally in four of the patients, accompanied by reduction in prevalence of deposit in three. This loss of dense deposits, characterized as a process of "dropping off," was complete in the free capillary walls of two of the patients.