The aim of this work was to assess the outcome of recombinant growth hormone (rGH) therapy in a large unselected group (72) of patients with Turner's syndrome (TS), 26 of whom have reached final height. Growth data were collected from Scottish patients with TS and outcome was assessed in three ways: response to therapy in the first year, response in subsequent years and final height. Phenotypic, auxological, genetic and biochemical factors, all of which may have affected the first-year response, were investigated. Fifty-one percent of the cohort had a clinically "good" first-year response to therapy and 49% had a "poor" response, a "good" response was defined as a change in the TS standard deviation score (SDS) of +0.5 or more and a "poor" response as a change in the TS SDS of less than +0.5. The percentage of children showing a positive change in TS SDS after 2, 3 and 4 years of therapy declined (88%, 78%, 41%). Mean (range) final height was 142.6 (133.4-153.6) cm, mean (range) pretreatment TS SDS was -0.27 (-2.1 to +1.09) and mean (range) final TS SDS was -0.05 (-1.4 to +1.59). Thirteen (50%) patients attained a final height that was greater than projected, eleven did not attain their projected final height and two achieved their exact projected final height. Short girls with TS appear to benefit more from rGH supplementation than tall girls, but otherwise there was no significant correlation between any of the parameters studied and the response to treatment. It is concluded that large-scale prospective studies are still required to assess the impact of rGH on final height in TS and to identify factors responsible for the variability in response.