A multicentre trial with recombinant somatropin was initiated in West Germany in early 1986. Acceptance of patients to the study was determined according to criteria outlined in a detailed study protocol. A total of 62 patients with GH deficiency has now been treated with recombinant somatropin for a minimum of 12 months. Of these, 34 were previously untreated and 28 had previously received pituitary GH. Recombinant somatropin, 12 IU/m2/week, was administered subcutaneously, divided into six doses. Height velocities increased from 3.4 cm/year (pretreatment) to 10.4 cm/year in the previously untreated group, and from 6.0 cm/year during the last year on pituitary GH to 8.3 cm/year for the previously treated patients. Tolerance of recombinant somatropin was good, and no anti-GH antibodies were detected in any of the patients.