In order to investigate the status of urinary kallikrein excretion (UKE) in various chronic renal diseases, we measured the UKE in 56 patients with chronic renal diseases. They ranged in age from 19 to 80 with 26 males and 30 females. Among them were 31 patients with primary glomerulonephritis (GN) without nephrotic syndrome, 8 with nephrotic syndrome, 10 with various renal diseases in the azotemic stage, 3 in the uremic stage and 4 with type I renal tubular acidosis (RTA) due to Sjögren syndrome. The primary GN patients who were on a low salt diet were classified as group II GN, while those who partook freely of salt were classified as group I GN. Thirty-six normal volunteers were enrolled as controls. Kallikrein activity was determined by enzymatic hydrolysis of synthetic chromogenic substrate S-2266. Urinary electrolytes were measured by flame photometry. The results showed that UKE was lower in patients with group I GN, azotemic or uremic patients and in patients with RTA, as compared with normal controls. If UKE was corrected by creatinine clearance (CCr), the UKE/CCr ratio was still lower in group I GN patients, but became higher in patients with azotemia and uremia. The UKE/CCr ratio was not different from that of controls or patients with RTA. In nephrotic patients, the UKE and UKE/CCr ratio were both higher than that for normal controls. However, in group II GN patients, neither UKE nor the UKE/CCr ratio differed from that of controls.(ABSTRACT TRUNCATED AT 250 WORDS)