Abstract. The effect of thyroid replacement therapy (TRT) was evaluated in 372 children with minimal thyroid dysfunction (MTD; augmented TSH response to TRH, deficient iodine consumption, goiter, short stature and retarded bone age), by comparison of pre‐with post‐observation height in periods of 6 months with and without TRT alternated. A significant ( P <0.05) height recovery was observed when children received TRT; however, during the period without TRT they showed a negative height recovery. Additionally, we followed 51 children with MTD who were observed from Tanner I until final height. The group with L‐thyroxine ( n = 43) during all follow‐up (97 months) showed an important recovery in height (SDS‐H = 1.67 ± 0.93 vs. 1.08 ± 0.74) which when compared with the untreated group ( n = 8; 114 months; SDS‐H = ‐1.50 ± 0.83 vs. ‐1.93 ± 0.33) was significant ( P < 0.001).