Abstract: Gamma dose response curve for phosphate (pi) release from dilute aqueous solutions of thymidine monophosphate (TMP) has been extended for very low and high doses, viz. 3 K rad to 200 K rad. Results show that Pi release in nitrogen saturated solution increases as dose increases. Possible reasons are discussed. The oxygen enhancement ratio for low doses is higher thaft what is reported earlier; whereas for high doses It is less than 1.