Urinary growth hormone excretion (uGH), expressed as the average of three consecutive nocturnal measurements, was studied in 324 prepubertal and pubertal children without (n = 188) or with (n = 136) growth disorders. In prepubertal control children (n = 127), the mean uGH was 11.9 +/- 4.9 ng/l without any correlation with sex or age. During puberty, a significant increase of uGH was observed in both sexes (boys: prepubertal 12.3 +/- 4.84 vs. pubertal 16.2 +/- 4.7 ng/l; girls: prepubertal 11.6 +/- 4.99 vs. pubertal 18.3 +/- 8.5 ng/l). In children with growth disorders, the results observed in various categories show a highly significant decrease in organic hypopituitary patients (p < 10(-6)) and obese subjects (p < 10(-6)) when compared to normal prepubertal children. In contrast, a significant increase was observed in 5 Laron-type dwarfisms (p < 10(-6)). However, in 24 children with partial growth hormone deficiency assessed by blood measurements (two pharmacological tests between 5 and 10 ng/ml), the results were not significantly different from the controls (13.6 +/- 6.4 ng/l). In a group of 66 children with short stature and normal blood response to pharmacological tests, uGH concentrations were significantly higher than those of the control group (17.3 +/- 8.71 ng/l, p < 10(-6)). The data suggest that uGH measurements lead to findings comparable to blood measurements, avoiding the disturbance of pharmacological tests, in well-delimited categories of patients. In contrast, uGH measurements are not the best way to detect partial GH-deficient children, but may be used to screen partial peripheral GH resistance in children with nonendocrine short stature.