Abstract: Effect of gamma radiation doses; 10, 20 and 30 Krads on yield and yield components of barley was studied in a replicated experiment during the year 2001-2002 at Cereal Crops Research Institute (CCRI) Pirsabak Nowshera NWFP. Except for 1000-grain weight, significant decrease in grain yield and yield components was observed with radiation doses. However, 1000-grain weight showed an increase as the radiation dose was increased. The findings of the study suggested that low doses up to 30 Krads of gamma radiation have direct inhibitory effect on some yield related traits in vegetative growth stage of barley. However, inhibitory effects on yield components related to reproductive stages in barley could not be fully understood which suggests further investigation.