Patients with advanced renal failure suffer from almost constant insulin resistance (IR) which is a major risk factor of atherosclerosis and very probably also of glomemlosclerosis. However, data on IR in kidney disease patients with mild-to-moderate kidney function decrease are lacking. A group of 52 patients with various kidney diseases and decreased kidney function of different degree but not with advanced renal failure was evaluated. Almost half of them suffered from IR though they did not differ from insulin-sensitive patients in age, sex, prevalence of various kidney diseases, hypertension, clearance of endogenous creatinine, serum creatinine, urea, uric acid, hippurate or pseudouridine concentrations. They did not differ in the prevalence and degree of metabolic acidosis or in the concentration of plasma and total and free magnesium in erythrocytes. They were just slightly more obese and their serum TG and VLDL concentrations were increased and HDL concentration decreased. It is concluded that IR and dyslipoproteinemia develop in the early stages of kidney diseases and could participate in kidney disease progression since the beginning of kidney disease. It is suggested that early treatment of these alterations could decrease the progression of kidney disease more effectively than their treatment in advanced stages.