In this method 20mg unirradiated/irradiated L-valine powder [(CH₃)₂CH.NH₂CH COOH] is dissolved in 10ml of a solution containing 4×10^-4 moldm ^-3Fe²⁺and 2.5×10^-4 mol dm ^-3xylenol orange (XO) in aerated aqueous 0.060mol dm^-3 sulphuric acid (FX). The plot of obsorbance at 550nm against dose is non linear. A dose of 1–50kGy can be measured. However, dosimeter can be sensitized in the dose range of 1to 16kGy by dissolving 50-mg valine powder in 10ml of a solution which contains 5×10^-4 mol dm^-3Fe²⁺and 3×10^-4 mol dm^-3XO in aerated aqueous 0.065mol dm^-3 sulphuric acid. The plot of absorbance at 549nm against dose is non-linear. However, dosimeter shows linear response when 500mg unirradiated/irradiated L-valine powder is dissolved in 10ml of a solution containing 7.5×10^-4 mol dm^-3Fe²⁺ and 3×10^-4 mol dm^-3 XO in aerated aqueous 0.25mol dm^-3 sulphuric acid. The plot of absorbance at 557nm against dose is linear in the dose range of 20–400Gy and doses down to about 1Gy can be measured using 10-cm path cells. Response of the dosimeter is independent of irradiation temperature in the temperature range 20–5^C Irradiated valine powder is stable for about 1month. The reproducibility of the method is better than 7 2%. This dosimeter is very useful as transfer dosimeter for food irradiation and radiation sterilization.