We have previously described (Medicine 56:493, 1977) 12 patients with diffuse lupus glomerulonephritis who had no clinical or laboratory evidence of renal involvement at the time of the initial biopsy. In this article we report the course of 10 of these patients followed for 5-11 yr (mean 83 mo). One patient died in renal failure and two others of related causes (septicemia and subarachnoid hemorrhage). Seven patients (Group I) had a benign course from a renal standpoint, with stable renal function and mild or no urinary abnormalities. Repeat biopsy in four patients in this group revealed near complete resolution of the original lesion in two and considerable improvement in two others, who now have primarily mesangial hypercellularity and a focal lesion, respectively. Renal function deteriorated in three patients (Group II), resulting in loss of congruent to 50% of GFR in two and renal death in the third. Repeat biopsy in one of these patients showed a more severe, albeit focal, glomerulonephritis. Prognosis for renal function appears better in patients with silent nephropathy, but larger numbers are required to substantiate this impression. Until definitive answers become available, we believe it prudent to biopsy SLE patients even in the absence of overt renal involvement and to treat those with diffuse proliferative glomerulonephritis.