Glucose-6-phosphate dehydrogenates (G6PD) deficiency is the most common defects of red blood cells among Iranian and Mediterranean people. Hypothyroidism is defined as thyroid hormone deficiency starting from the time of birth. Thyroid hormones influence the activity of lipogenic enzymes such as glucose-6-phosphate dehydrogenase and malic enzyme. This study aimed to determine the rate of hypothyroidism in patients with G6PD deficiency. After 120 days, the newborns that administered drug and diet for hypothyroidism were checked for TSH and G6PD enzyme. 2287 out of 23260 screened babies were afflicted with favism (512 females and 1775 males). 42 cases were hypothyroid among who 35 had G6PD deficiency. However, after 120 days of treatment with Levothyroxine, 23(85%) patients of them had normal levels of G6PD.It shows that their deficiency had no genetic origin. Base on these findings of this study, the newborns with G6PD deficiency should be checked for thyroid hormones. Moreover, in the hypothyroid patients, checking the level of G6PD is recommended.