Irradiation of Ephestia caplets (Walk.) full grown male pupae with substerilizing doses (150 and 250 GY) reduced deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) content in male parents (P) and also in males and females of Fl and F2 progenies. Irradiation of full grown male pupae with 250 GY increased total protein content in parents, while de­creased it in their Fl and F2 progenies. The reduction of both nucleic ac­ids and total protein was higher in F2 progenies than Fl progenies than P. Irradiation of full grown pupae with 150 and 25 GY induced inher­ited sterility, Fl males were more affected than Fl females. The possibil­ity of correlation between the reduced number of progenies and the re­duction of nucleic acids and total protein have been discussed.