Growth deficiency is one of the most frequent causes of referral to Endocrinology Outpatient Clinic. IGF-1 (insulin-like growth factor 1) deficiency is one of the rarest causes of short stature. In 2009 in Poland a therapeutic programme was set up for children with severe primary IGF-1 deficiency. The authors present the data of three first polish patients qualified for the rhIGF-1 (recombinant human insulin-like growth factor 1) - mecasermin. The authors conclude that the treatment with rhIGF-1 significantly improves growth velocity in patients with IGF-1 deficiency. During two years of mecasermin treatment no serious side effects were noted.