Cardiovascular disease is the major cause of death in chronic renal failure (CRF) patients managed by dialysis or kidney transplantation. Whilst the use of human growth hormone (hGH) is of established benefit in CRF children particularly in those with short stature, in the present study we assessed in CRF children the effect of hGH treatment on circulating lipoprotein(a) [Lp(a)], a genetically determined cardiovascular risk factor. We studied 15 CRF children treated by dialysis or conventional therapy and after kidney transplantation. Overnight fasting blood samples were collected immediately before and after 6 months hGH treatment. In all but one of the children there was a significant increase in serum Lp(a) over the 6 month treatment period - +66.7% over the basal levels (range 14 to 180%). After the hGH treatment, in six children Lp(a) levels were elevated to above 300 mg/l, the cut-off level for increased coronary artery disease (CAD) risk. Concomitantly children also had an increase in serum levels of IGF-I (+96.4%) and insulin (+85.8%). All children had an accelerated growth velocity during the treatment; there was no effect on serum creatinine. Our study shows that hGH treatment in CRF children, though beneficial in its growth promoting effects, increases the already characteristically high levels of serum Lp(a), a risk factor for CAD, and that serum Lp(a) monitoring during treatment with hGH may be useful in evaluating future cardiovascular risk.