An experiment was carried out to evaluate the main causes of broiler carcass condemnations in shazand industrial slaughter during the first six months of 2009. Poultry industry occupies a major position in the livestock sector of agricultural production because birds reproduce much quicker to produce meats and eggs for human consumption. Several of the post-mortem inspection conditions that are currently recorded have been identified as potential indicators of on-farm management problems. The data was taken within six months period and carcass condemnation causes were separately recorded based on monthly. In this study six different cause of carcass condemnation were revealed that included septicemia, excessive atrophy, toxicosis, trauma, respiratory infection and peritonitis ascites. Base d on this result excessive atrophy, trauma and septicemia with 32, 23 and 13 percentage of total condemnation frequency respectively was main cause of carcass condemnation and toxicosis with 9 percentage of total carcass condemnation was least importance of ones.Result of statistical comparison revealed that in different months of experiment about probability of different cause of condemnation was least significantly (p<0.05) in May except excessive atrophy and trauma. There were no significant differences (p>0.05) between frequency of each cause of carcass condemnation in different month of experiment except May. In our study there was significant difference between seasons (spring and summer), the peritonitis ascites, toxicosis, respiratory infections and septicemia have higher frequency rate at summer but trauma and excessive atrophy has higher frequency rate at spring. This difference may occur because of environment conditions that were high in temperature at summer months. On the basis of the results of this study, it was concluded that that excessive atrophy, trauma and septicemia were main cause of condemned carcass of bird in shazand industrial slaughter house within one