The hydrogen uptake behavior of two types of Zircaloy-4 specimens containing fine or coarse Zr(Fe,Cr) 2 precipitates was studied at 623–723 K in the pre-transition period of oxidation in steam. The amount of hydrogen uptake of the specimen containing fine precipitates was smaller than that of the specimen containing coarse ones, and the former was independent of the oxidation temperature while the latter increased with decreasing temperature. These results were successfully explained with the model that the Zr(Fe,Cr) 2 precipitates remaining unoxidized act as the short-circuiting route in the hydrogen transport through the oxide film. The amount of hydrogen uptake of the present Zircaloy-4 specimens containing coarse precipitates was larger than that of the Zircaloy-2 specimens containing comparable sizes of precipitates. This was attributed to the fact that the concentration of precipitates remaining unoxidized in the oxide film of Zircaloy-4 was higher than that of Zircaloy-2.