Background: Fear can harm the welfare and productive performance of intensively housed chicks and resulted in lowered fear adaptability to automation and human contact. The purpose: This study was designated to measure fear levels to co-workers and its relation to productive performance in the most commonly reared commercial broiler strains (Avian 43, Hubbard, Ross and Cobb) in Upper Egypt when they were kept under intensive rearing conditions. Methods: In this study, measurement of fear levels in broiler strains was investigated according to various test situations. Firstly, using acute fear tests on individual and farm levels to differentiate between strains behaviors, Secondly the productive traits such as growth rate, mortality rate and feed conversion efficiency were measured at farm level during 7 weeks periods. Results: There were significant differences between strains in terms of fear and productive performance (P<0.05). High fear levels were found to be associated with high productive performance in Ross and Cobb broilers. Conclusion: This study indicated that fearfulness was positively correlated to high productive performance e.g. Body weight gain and feed efficiency. In conclusion, selection towards high productivity could increase fearfulness in Ross and Cobb broilers when compared with Avian 43 and Hubbard.