Neonatal screening for congenital hypothyroidism using cord serum thyroid-stimulating hormone (TSH) was initiated in Najran health region in September 1990. A total of 30810 newborn infants were screened by April 1995. Of the 24 infants with abnormal thyroid function tests on recall, 22 had permanent primary congenital hypothyroidism (incidence; 1:1400) and in two male siblings transient congenital hypothyroidism (incidence; 1:15400) was proved on follow-up. There was a significantly higher incidence of dyshormonogenesis. Eight (57 per cent) of the 14 infants who were adequately studied thyroid scan revealed ectopic glands with increased 99mTc uptake, while thyroid ectopy and aplasia were present only in three (22 per cent) infants each. Furthermore, goiter was evident clinically in two other patients.