AIMThe optimal GH regimen, in terms of cost-effectiveness, in children with normal GH immunoreactivity but reduced bioactivity is still debated. METHODSIn 12 GH-deficient (GHD) and 12 bioinactive GH children undergoing GH treatment we evaluated the increase in growth velocity, the difference between target height and final stature and the incremental cost-effectiveness ratio. RESULTSWe found a significant (p < 0.05) increase in growth velocity in both groups during the first year of GH treatment (non- GHD: from -1.7 to 5.4 SDS; GHD: from -1.46 to 4.74 SDS). There was no statistically significant variation between the two groups in the difference between final height and target height. We did not find any significant difference in cost/height gain between GHD (1925.28 ± 653.15 euro) and bioinactive GH children (1639.55 ± 631.44 euro). There were also no significant differences in cost/year of therapy between GHD (12347.68 ± 2018.1 euro) and bioinactive GH children (11355.08 ± 1747.61 euro). CONCLUSIONIn children with reduced GH biological activity, confirmed by the increase of serum IGF-I levels during generation test, the cost of GH treatment is justified by the positive results obtained in growth and adult height as in classical GHD patients.