Endemic goiter is one of the health effects of iodine deficiency. Enlargement of the thyroid is often seen during pregnancy especially in the endemic iodine deficiency disorders (IDD) areas. Thyroid hormones have a vital role in the fetal development and maturation of the brain. The lack of these hormones may result in neurological damage. We measured thyroid hormones and TSH in cord blood and TSH in newborn's blood from dry blood spots on filter paper in 5-14 th days, from 58 non goitrous and 61 goitrous mothers. T4, T3 and TSH concentrations in cord blood were measured by enzymeimmunoassay (EIA) using enzymum test Boehringer and TSH from dry blood spots on filter paper were measured by radioimmunoassay (RIA). Goiter size was graded as follows: O, I, II and III. There were significant differences in cord serum T3 concentrations between non goitrous and goitrous mothers with grade I, II and III. TSH concentration in newborn's blood from goitrous mothers of grade III were significantly higher than those from non goitrous mothers and from goitrous mothers of grade I. T4 concentration in cord blood from non goitrous mothers in IDD area was significantly lower than those from non IDD area and those from goitrous mothers in the IDD area. There were significant differences also between TSH concentration in newborn's blood spots from goitrous mothers in IDD area and those from goitrous mothers in non IDD area and from non goitrous mothers in IDD area. Two cases of congenital hypothyroidism were found in infants from goitrous mothers.(ABSTRACT TRUNCATED AT 250 WORDS)