Infectious bronchitis virus (IBV), Avian influenza virus (AIV) and Mycoplasma gallisepticum (MG) have been recognized as the most important pathogens in poultry cause acute respiratory infection and serous economic problems in Iraq and many other countries all over the world. This study was conducted to investigate the distribution of these diseases in commercial chicken flocks in different geographical region in middle part of Iraq by using qPCR. Tracheal swabs and tissue specimens from trachea, lung and kidney were taken from 38 different cases from commercial broiler chicken flocks in (Najaf, Hilla, Muthana and Theqaar governorates) in the period from November 2010 to June 2011, all these flocks were showed respiratory symptoms and mortality about 20-90%. The results showed that 92.1% of samples collected from these flocks were infected with IBV, 20% of samples were infected with IB alone and 45.71% of samples with IB combined with both GM and AIV subtype H9 and 25.71% of samples were positive to both IBV and AIV(H9). No samples were positive to AIV (H9) or MG alone. Because of importance of respiratory diseases as a most common conditions noted in commercial flocks in Iraq and no previous study detecting this pathogens by molecular techniques, this study come to detect and confirm the diagnosis of this pathogens by qPCR as new technique used in this field in Iraq.