Studies were carried out to investigate the effects of sunn pest damage on thousand grain weight, protein content and sedimentation value of bread wheat (Triticum aestivum) genotypes grown under natural sunn pest infestation during 1993-94, 1994-95, 1995-1996. Sunn pest damage varied among wheat genotypes. Thousand grain weight, protein content and sedimentation values were decreased significantly as sunn pest damage increased. Decrease in thousand grain weight, protein content and sedimentation value due to sunn pest damage recorded was 17.7, 18.2 and 77.2%, respectively. Wheat genotypes with hard red grains were less affected from sunn pest damage than soft white grains. Results of this research demonstrate the existence of substantial variation among wheat genotypes in the damage due to sunn pest that gives opportunity for selection of less damaged wheats which can be grown directly for production and use in wheat breeding programmes to improve resistance against sunn pest.