The dependence of the distribution of latent image on radiation energy was studied in X- and γ-ray radiography. Measurements were carried out for nine sorts of industrial X-ray films of three manufactures and four sorts of other type films. As radiation sources, a visible blue light source, super soft and 180 kVp X-ray generaters, Cs-137 and Co-60 γ-ray sources and a 15 MeVp industrial betatron were used. For the development of films, D-19 b (total developer), surface developer (glycine used) and internal developer (added sodium thiosulf ate to D-19 b developer) were used, and as the bleaching solution, potassium ferricyanide solution and potassium dichromate solution were used. From the experimental results, it was found that regardless of the type of films the largest amount of internal latent image was obtained when they were irradiated with radiations of 90-160 kVp, and that in energy regions higher and lower than this, internal latent image shows a tendency to decrease in amount. This shows that the amount of internal latent image increases with the density of ion pairs produced in emulsion grains. Thus an energy dependence is observed for the distribution of latent image in X- and r-ray radiography.