The clinical course of murine hereditary nephrotic syndrome (ICGN strain) was determined by examining 201 animals under different conditions. In the early stage, significant hypoproteinemia and hypoalbuminemia developed (p < 0.001) in parallel with a progressive rise in urinary protein concentration (p < 0.001). In the middle stage, the concentrations of total cholesterol, triglyceride, and β-lipoprotein markedly increased (p < 0.01, p < 0.001, and p < 0.001, respectively), suggesting that type lib hyperlipoproteinemia developed as in human nephrotic patients. Systemic edema appeared in 8 of 24 animals. In the terminal stage, both BUN and creatinine values greatly increased (p < 0.001), indicating rapid deterioration of renal function. The present study suggests that ICGN mice could be a useful model to study the pathophysiology of human nephrotic syndrome and its progression to renal failure.