Hypertrichosis in a newborn girl infant of a diabetic mother with congenital hypothyroidism is reported. Both neonatal hyperinsulism and increased testosterone levels were documented. The hypertrichosis resolved after 3 months' of thyroxine replacement treatment. The possible causal association between hypothyroidism, and hypertrichosis has not been previously reported in neonatal period. Thyroid function should be evaluated in all newborn babies with hypertrichosis or abnormal distribution of body hair.