This report describes the case of a 57-year-old man who underwent a repeated renal biopsy 25 years after the first biopsy in which the diagnosis of IgA nephropathy was made. Although the patient exhibited gradually increasing proteinuria and a slowly progressive renal impairment, the histological findings of the repeat biopsy revealed no evidence of either glomerular inflammatory changes or IgA deposition. Instead, a marked decrease in the glomerular density and hypertrophy of the remnant glomeruli were noted. Almost a complete disappearance of urinary protein excretion by a calorie-restricted diet indicated that the patient's obesity and its related factors may have contributed to the present nephropathic development.