Dense deposit disease (DDD) is a rare disorder that most commonly affects children. This study reports the largest North American series addressing clinicopathologic and outcome differences in children and adults.Thirty-two patients with DDD were analyzed from the archives of Columbia University between 1977 and 2007. Characteristic intramembranous electron-dense deposits defined all diagnoses.The cohort included 14 children (60 yr. The female/male ratio was 1.9. At presentation, the mean 24-h urine protein was 4.6 g, nephrotic syndrome was present in 33%, renal insufficiency in 59%, and hematuria in 87% of patients. Compared with adults, children had lower incidence of renal insufficiency and were more likely to have reduced C3. Histologic pattern included membranoproliferative, mesangial, endocapillary, and crescentic glomerulonephritis. Treatment included immunosuppression (IS) alone in seven, renin angiotensin system (RAS) blockade alone in six, and combined IS/RAS blockade in 11. On follow-up (mean 63 mo) available in 27 patients, 26% had complete response, 48% had persistent renal dysfunction, and 26% had ESRD. Correlates of ESRD were older age and higher creatinine at biopsy, the absence of combined IS/RAS blockade therapy and the presence of subepithelial humps, but not histologic pattern. On multivariate analysis, age and creatinine emerged as the only independent predictors of ESRD.DDD is clinically and pathologically heterogeneous. Adults have worse outcome than children, despite similar treatment. Combined IS/RAS blockade appears superior to either agent alone.