Height and weight growth before and during treatment with human growth hormone (hGH) was studied in 46 Dutch patients treated for craniopharyngioma. Weight was expressed as body mass index (BMI, weight/height). At the time of tumor treatment mean +/- SD height standard deviation score (SDS) was -1.22 +/- 1.38 and BMI SDS was 0.56 +/- 1.32. The initial height SDS was inversely related to age (r = -0.38; p < 0.02). Before hGH treatment height SDS decreased to - 1.57 +/- 1.08 (p < 0.05) and BMI SDS increased to 1.54 +/- 1.58 (p < 0.005) during the first year after tumor treatment. Changes in height SDS correlated positively with basal prolactin (PRL) levels (r = 0.46; p < 0.05). Neither tumor localization nor treatment mode was related to changes in height SDS and BMI SDS. Forty patients were treated with hGH, started a median interval of 2.0 years after tumor treatment. At the time of the start of hGH treatment height SDS in these patients was -1.70 +/- 1.13, and BMI SDS was 1.44 +/- 1.79. During treatment with hGH, height SDS increased to -1.05 +/- 1.10 (p < 0.001) in the first, and to -0.80 +/- 1.04 (p < 0.001) in the second year. BMI SDS did not change during hGH therapy. In conclusion, there is a large variation in height SDS and BMI SDS at the time of initial presentation as well as during spontaneous growth after tumor treatment. Spontaneous growth is related to serum PRL concentrations. Treatment with hGH significantly increased height SDS during the first 2 years, whereas BMI SDS did not change.