Primary congenital hypothyroidism is a common preventable cause of mental retardation. Neonatal thyroid screening is highly successful in early diagnosis and the improvement of developmental prognosis in the hypothyroid neonate. However, rarely cases could be missed, so doctors must be aware of the earl symptoms and signs of hypothyroidism. Therefore, the purpose of this study was to emphasize the presenting clinical features of primary congenital hypothyroidism at the age of diagnosis. The study population included 17 children with primary congenital hypothyroidism who attended the Department of Pediatrics, University Clinical Center Tuzla between 1986 and 1999. The diagnosis of all patients was confirmed by serum thyroid function tests (T4 and TSH). Of the 17 patients 10 (58.8%) were diagnosed in the first three months of life and 3 of them (17.6%) between fourth and sixth month of life. Four children (23.5%) were diagnosed after the age of six months. In the first three months of life hypothermia, constipation, jaundice, poor feeding, hoarse cry, macroglossia and hypoactivity were the moste common symptoms. Among the 17 patients with primary congenital hypothyroidism 5 of them (29.4 %) were diagnosed to have disgenetic thyroid tissue and 12 (70.6%) as having dyshormonogenesis. TSH and T4 levels were higher in patients in whom thyroid tissue was dysgenetic as comapared with those with dyshormonogenesis but the difference was not statistically significant (p > 0.05). Now it is expected that neonatal screening program in Bosnia and Herzegovina Federation will contribute to the detection of primary congenital hypothyroidism in early days of life. However, until an effective screening test is not yet routine in whole country, paediatricians should consider the diagnosis of hypothyroidism whenever it is clinically suggested.