We investigated the plasma and urinary growth hormone (GH) levels, and plasma insulin-like growth factor (IGF-I) in 15 (8 prepubertal and 7 pubertal) subjects with chronic renal insufficiency. Four of our 7 pubertal patients had a short stature (standard deviation score from -2.7 to -4.0). Significantly increased plasma GH and IGF-I levels were found in pubertal subjects alone (p less than 0.05). The urinary GH levels was significantly increased in prepubertal and pubertal subjects (p less than 0.001 and 0.05, respectively). A significantly inverse correlation between urinary GH excretion and creatinine clearance was found (r = -0.55; p less than 0.05). Increased plasma GH, IGF-I and urinary GH levels seem to suggest a complex alteration of GH and somatomedin metabolism in central and peripheral (receptor) cells.