The purpose of this study is to further determine whether benazepril, could safely slow the progression of renal dysfunction in non-diabetic patients with advanced renal insufficiency.

Inclusion Criteria:

1. serum creatinine concentration 1.5-5.0 mg/dL (133-442 µmol/L)
2. creatinine clearance 20 to70 mL/min/1.73 m2, with variations of less than 30 percent in the three months before the screening evaluation
3. non-diabetic renal disease
4. persistent proteinuria (defined as urinary protein excretion greater than 0.3 g/day for three or more months without evidence of urinary-tract infection or overt heart failure [New York Heart Association class III-IV]).

Exclusion Criteria:

• immediate need for dialysis; treatment with corticosteroids, non-steroidal anti-inflammatory drugs or immunosuppressive drugs; renovascular disease; myocardial infarction or cerebrovascular accident in the year preceding the trial; connective-tissue disease; obstructive uropathy.