ANCA-associated glomerulonephritis may present initially with renal symptoms, especially in elderly patients. We report a case of ANCA-associated glomerulonephritis in an 80-year-old female presenting with renal insufficiency and proteinuria. There was no evidence of systemic illness at admission. The major finding in the renal biopsy was the presence of granulomas. Additional testing for anti-neutrophil cytoplasmic antibodies (ANCA) was suggested. The ANCA test was positive confirming the diagnosis of ANCA-associated necrotizing/granulomatous glomerulonephritis. The patient responded well to adequate treatment with immunosuppressive therapy. This case demonstrates the importance of the renal biopsy in cases of ANCA-associated glomerulonephritis presenting with renal symptoms.