Growth rate, skeletal maturation and thyroid function were measured in fifty thalassaemic children (age 2-13 years) and in fifty controls (matched for sex and age who were not anaemic. Growth retardation was present in several patients during the first years of life and affected almost all subjects examined when they were approaching puberty. Discrepancy between bone and height age in patients was not significantly different from controls. The finding of low T4 and T3 with a high TSH indicated thyroid hypofunction. This finding, already present early in life, did not worsen with increasing age. In beta-thalassaemia hypothyroidism cannot be the cause of retarded growth since there is no relationship between the impairment in thyroid function and severity of growth retardation. In addition, height age was not different from bone age, while a discrepancy is a constant feature of low stature due to hypothyroidism.