The long-term course of 56 patients with systemic lupus erythematosus who had precisely defined renal histology and carefully assessed clinical status at the time of their initial renal biopsy prior to 1976 was evaluated and analyzed by life-table analysis. The average length of follow-up has now been greater than 10 years since initial biopsy. Patients with mesangial lesions (World Health Organization [WHO] classes IIA and IIB) had a more favorable renal and patient survival at five and 10 years than did patients in the other WHO classes (III, IV, and V). Individual renal histologic features of activity and chronicity when combined into an activity index and a chronicity index did not significantly predict renal survival in this population, nor did the presence of hypertension or renal dysfunction at the time of the initial renal biopsy significantly influence renal or patient survival. Patients with the nephrotic syndrome at initial biopsy had a poorer renal survival than did patients without the nephrotic syndrome. However, patients who experienced a remission of the nephrotic syndrome fared better in terms of both renal and patient survival than did those patients without a remission. By life-table analysis, patient survival was significantly better for patients in whom biopsy was performed after 1973 than for those in whom biopsy was performed prior to that time despite similar clinical features and WHO histology in each group interval. Our data suggest that improved survival for patients in recent studies may relate to better supportive care and more selective use of immunosuppressive therapy in patients with milder forms of lupus nephritis.