In radiation field certain workers and patients are subjected to varying levels of intermittent radiation delivered in certain cases as whole body exposure. The purpose of this study is to explore, the effects of combined exposure of rats to successive doses of gamma radiation following nicotine injection. The pharmacological role of vitamin C and its potential radioprotective capacity was assessed on the serum thyroid hormons levels during the first hours of the treatments. The results indicated generally significant increases in the levels of serum thyroxine [T4], free T4 and T4/T3 ratio. However the level of triiodothyronine [T3] exihibited significant decrease especialy with 5-successive doses of vitamin C [at 100 mg/kg of body weight] intake every other day alone. The same results are observed when the latter doses of Vitamin C are accompanied by daily exposure to 0.7 Gy gamma radiation for ten days. Administration of vitamin C after every other fraction either of radiation exposure or nicotine injection or both produced some amelioration in the changes of T4,T3 and F.T4 levels.