A study comprising 41 males, 5 females of the age ranging from 28 to 56 years was conducted during Ramadan of 1989 to compare T3, T4 and TSH levels in fasting with the levels of non-fasting conditions. Each individual gave 6 blood samples: One sample was taken 20 days before the onset of Ramadan, 3 samples at different fasting days and last two samples were drawn 23 days and five months after the end of Ramadan, respectively. The results showed a significant gradual rise in TSH throughout the fasting month, although the mean levels remained within normal limits. Pre- Ramadan levels were re-attained well after the end of Ramadan. There was no significant change in T3 and T4 levels.