In 22 patients with congenital adrenal hyperplasia (CAH), the effect of treatment on growth was evaluated retrospectively. The degree of control with treatment had generally been assessed by measurements of serum 17-hydroxyprogesterone (17-OHP) and/or urinary pregnanetriol levels. In 20 patients, there were no significant differences in both height SDS for bone age (-2.05 +/- 1.89 vs -1.85 +/- 1.30) and height SDS for chronological age (CA) (0.23 +/- 1.94 vs -0.36 +/- 1.81) in a mean uninterrupted treatment period of 5.80 +/- 3.58 years. Further analysis in salt-losers and nonsalt-losers separately showed that height SDS for bone age had decreased in the salt-losers and had increased in the nonsalt-losers. Six patients had signs of early puberty. In 22 patients, there was a negative correlation between the prednisolone dose on one hand and height velocity SDS for CA and bone age velocity on the other. It was also found that the mean serum levels of 17-OHP did not always reflect the degree of long term control measured by auxological parameters. These findings indicate that our treatment in the patients did not result in a significant improvement in height prognosis. We can conclude that growth prognosis in CAH patients can be improved by relying on auxological parameters rather than serum 17-OHP and urinary pregnanetriol levels for monitoring control. Special attention should be paid to salt-losers in this respect.