Abstract: Dwarfing gene is of interest among scientist, because of its numerous pleiotropic effects in physiology, nutrition and pathology. Also, the naked neck (Na) gene has received great attention for poultry production, because of their association with heat tolerance. From this view, An experiment was conducted to evaluate the effect of sex-linked dwarf (dw), autosomal naked neck (Na) and double segregation genes on laying performance and some hematological parameters of egg-type chicken under prevailing condition of Egypt. Three hundred brown Dahlem (Germany strain) hens from four genotypes {normal body size-normally feathered (Dw-nana), dwarf size-normally feathered (dw-nana), normal body size-naked neck (Dw-Nana) and dwarf size-naked neck (dw-Nana)} were reared under the same environmental, managerial and hygienic conditions from 20 to 40 weeks of age. The results obtained showed that the sex-linked dwarf (dw) gene significantly reduced body weight, egg mass and egg number compared to normal body size sibs. On the other hand, the dwarf birds had significantly consumed less feed and better feed conversion ratio. With respect to internal and eggshell quality, it could speculate that the presence of dw gene associated with higher yolk percentage, higher haugh units and thicker eggshell thickness than that of normal body size counterparts. Concerning hematological parameters, the presence of dw gene significantly reduced plasma T3, plasma cholesterol and liver enzymes compared to normal body size hens. The opposite trend was noticed for both total lipids and triglycerides. In contrary to dw gene, the Na gene had a better effect on laying performance parameters of egg-type chicken. With respect to double segregation genes, it could be noted that the introducing Na gene could compensate the reducing effect associated with dwarfing (dw) gene on laying performance measurements and some hematological parameters. In conclusion, the loss of revenue due to reduction in egg production associated with sex-linked dwarf gene may be exceeded by revenue saved from lower feed intake and better feed efficiency. Moreover, incorporating the Na gene into dwarfed birds could compensate the reduction effects associated with dwarfing (dw) gene.