Urinary vitronectin excretion was measured by ELISA in healthy and various renal diseases children. In 36 healthy children, urinary vitronectin was excreted at low levels in the range of 0-2.71 (0.187 +/- 0.655) micrograms/g.Cre. Urinary Vitronectin and the positive ratio in various renal diseases were as follows: IgA nephropathy: 0-59.22 (3.420 +/- 9.180) micrograms/g.Cre, 41%; Henoch-Schönlein purpura nephritis: 0-118.40 (19.619 +/- 31.713) micrograms/g.Cre, 53%; membranous nephropathy: 0-2.76 (0.595 +/- 0.885) micrograms/g.Cre, 18%; membrano-proliferative glomerulonephritis: 0-11.00 (1.888 +/- 3.078) micrograms/g.Cre, 33%; acute glomerulonephritis: 0.07-0.84 (0.456 +/- 0.317) microgram/g.Cre, 0%; Alport's syndrome: 0.81-112.12 (32.378 +/- 44.038) micrograms/g.Cre 67%; focal segmental glomerulosclerosis: 0.30-31.86 (12.070 +/- 17.241) micrograms/g.Cre, 67%; idiopathic nephrotic syndrome with proteinuria: 0-2.89 (0.551 +/- 1.064) micrograms/g.Cre 17%; idiopathic nephrotic syndrome in remission: 0-0.97 (0.258 +/- 0.372) microgram/g.Cre 0%, respectively. In patients with chronic renal failure, urinary vitronectin was excreted at high levels in the range of 2.15-446.08 (118.696 +/- 144.338) micrograms/g.Cre and the positive ratio of urinary vitronectin was 100%. In IgA nephropathy, Henoch-Schönlein purpura nephritis, membrano-proliferative glomerulonephritis, Alport's syndrome, focal segmental glomerulosclerosis and chronic renal failure, the positive ratio of urinary vitronectin was higher than in healthy children, but in membranous nephropathy, acute glomerulonephritis, idiopathic nephrotic syndrome with proteinuria and in remission, the positive ratio of urinary vitronectin was not significantly different from that of healthy children.(ABSTRACT TRUNCATED AT 250 WORDS)