The objective of this study was to find out whether moderate doses of growth hormone (GH) in combination with oxandrolone (Ox) and late initiation of puberty could improve adult height even in relatively old patients with Ullrich-Turner syndrome (UTS). Ninety-one patients with UTS were randomly assigned to receive either GH alone (Saizen, Ares-Serono, Geneva) 18 IU/m2/week (0.2 mg/kg/week) by daily s.c. injections (group GH) or a combination of GH and Ox 0.1 mg/kg/day p.o. (group GH + Ox). Prior to treatment mean age was 10.2 years (GH) and 10.5 years (GH + Ox), mean projected adult height (PAH) was 146.4 cm (GH) and 146.7 cm (GH + Ox). During year 2 the GH dose was increased in the GH group to 24 and later to 28 IU/m2/week (0.27 mg and later 0.31 mg/kg/week). In group GH + Ox, the Ox dose was reduced to 0.05 mg/kg/day after the first 12 months of therapy, and during the last treatment years the GH dose was raised to 24-28 IU/m2/week (0.27-0.31 mg/kg/week) due to declining growth promotion. Some of the patients of group GH were later given Ox in addition to GH because of waning growth velocity, whereas some of the patients of group GH + Ox were taken off Ox due to virilizing side-effects of the high Ox dose, thus making up a third group of patients: group GH + transient Ox. Puberty was induced at a mean age of 14.9 years. In group GH + Ox, cumulative growth during 5 years of therapy was twice the growth anticipated from standards of untreated patients with UTS. Forty-seven patients are now near or at final height: in group GH (n = 7), mean final height was 151.7 cm (PAH 148.1 cm, gain 3.6 cm); in group GH + Ox (n = 15), 155.1 cm (PAH 147.2 cm, gain 7.9 cm); and in group GH + transient Ox (n = 25), 152.8 cm (PAH 146.4 cm, gain 6.4 cm). These results should be regarded as an underestimate of true final height since some the patients are still growing. Moderate doses of GH plus Ox and late induction of puberty definitely improved final height even in patients with UTS treated relatively late.