Aim: To describe a group of neonates with congenital, non-traumatic chylothorax, one of whom developed transient hypothyroidism following treatment with somatostatin. Methods: The charts of seven infants with congenital chylothorax were reviewed in terms of their clinical presentation, the severity of their disease, the complications they presented and the duration of their hospitalization. Their pituitary-thyroid axis function was monitored in particular. Results: The seven infants, all preterm (32-34wk), suffered from congenital chylothorax and hydrops fetalis diagnosed during the prenatal period. Four were treated by intrauterine drainage, and four had congenital malformations. Hospitalization lasted from 32 to 120 d. Three of the infants suffered from thrombocytopenia, three had chronic lung disease, and one suffered from Gram-negative sepsis. The infant treated with somatostatin initially had normal thyroid function, but later developed primary transient hypothyroidism and was treated with L-thyroxine. The thyroid screening tests for the infants who were not treated with somatostatin were all normal. Conclusions: Repeated doses of somatostatin were effective in reducing chylus production. Administering this treatment earlier should be considered in order to minimize known complications. The only potential side effect observed was primary transient hypothyroidism. Therefore, careful monitoring of the pituitary-thyroid axis is advised. Aim: To describe a group of neonates with congenital, non-traumatic chylothorax, one of whom had transient transient hypothyroidism following treatment with somatostatin. Methods: The charts of seven infants with congenital chylothorax were reviewed in terms of their clinical presentation, the severity of their Results: The seven infants, all preterm (32-34 wk), suffered from congenital chylothorax and hydrops fetalis diagnosed during the prenatal period Three of the infants suffered from thrombocytopenia, three had chronic lung disease, and one suffered from Gram-negative sepsis. The infant treated with somatostatin initially had normal thyroid function, but later developed primary transient hypothyroidism and was tre The thyroid screening tests for the infants who were not treated with somatostatin were all normal. Conclusions: Repeated doses of somatostatin were effective in reducing chylus production. Administering this treatment earlier should be considered in order to minimize known complications. The only potential side effect observed was the primary transient hypothyroidism. Therefore, careful monitoring of the pituitary-thyroid axis was advised.