Eight GH-deficient children were treated with GHRH (1-44), once daily s.c. for 6-18 months. At the 6th month of therapy, 3 patients showed a catch-up growth ("responders"), while the remaining 5 did not ("non-responders"). In all patients treatment was discontinued after 6-18 months, when its effect on growth rate failed. After a wash out period of at least 6 months, patients were submitted to biosynthetic GH therapy. After 6 months of GH treatment a significant catch-up growth was found in both responder and non-responder children. GHRH therapy is found to be less effective than GH treatment. Other methods of GHRH administration are worth investigating.