As the numbers of aging patients with manifestations of renal disease increase, the elderly must frequently undergo renal biopsies. This study examined the characteristics of clinicopathological correlations in elderly patients. Medical and clinical records from renal biopsies registered in two hospitals between January 2000 and December 2004 were reviewed. Among 406 patients (female: male 224/182; age 43.9 +/- 18.8 years, mean +/- SD) who underwent renal biopsies, 61 (15.1%) who were aged 65 years and older (female: male, 29/32; age 72.8 +/- 5.2 years) were selected. The elderly usually underwent percutaneous renal biopsies for renal diseases such as nephrotic syndrome (43%) and acute or rapidly progressive renal failure (A/RPRF, 39%). Focal/segmental glomerulosclerosis (23%), minimal change disease (19%), and membranous nephropathy (15%) are frequently diagnosed based on biopsy specimens from patients with nephrotic syndrome. Among patients presenting with A/RPRF, 17 (71%) and 4 (17%) had pauci-immune, MPO-ANCA positive, crescentic glomerulonephritis and interstitial nephritis, respectively, and benefited from therapeutic intervention. Histopathological and pre-biopsy clinical diagnoses differed in nine (15%) patients. The complication rate after biopsy was low (3%). Primary glomerular diseases presenting with nephrotic syndrome and primary crescentic glomerulonephritis associated with rapidly progressive renal failure were the most frequently diagnosed among the elderly who underwent renal biopsy. Percutaneous renal biopsy provides clinically useful information about the elderly because clinical presentation and the predicted diagnosis sometimes vary.