One hundred quails of different ages were collected from private and governmental farms. Out of these, eighty (80) quails were from flocks suffering from respiratory manifestations (Coughing, sneezing, railing, wet eyes, nasal discharge and sometimes swollen of infraorbital sinuses either bilateral or unilateral) and the remaining twenty (20) quails were apparently healthy ones. Bacteriological examination revealed that 16 isolates M. gallisepticum were recovered with an over all incidence of 16.0%. Regarding the distribution and frequency of occurrence of Mycoplasma species isolated from quails in relation to the age of examined birds it can be concluded that quails aged more than 8 weeks showed the highest incidence of M. gallisepticum (9.0%), then quails aged 7-8 weeks (2.0%) followed by those aged one to six weeks (1 2 %). M. gallisepticum strains were isolated with higher incidence from trachea (10.0%) followed by lungs (6.0%). Biochemical identification of Mycoplasma species recovered from examined quails revealed that, the isolated Mycoplasma gallisepticum (16 isolates) were positive for glucose fermentation and tetrazolium reduction tests; in contrast, they were negative for arginine hydrolysis test. Serological typing of mycoplasma isolates by using growth inhibition test (G.I.T.) and growth precipitation test (G.P.T) revealed that 15 isolates obtained from diseased
quails showing respiratory affection were identified as M. gallisepticum (18.8 %). Meanwhile, one isolate obtained from apparently healthy quails also was identified serologically as M. gallisepticum with an incidence of (5.0%). From the obtained results, it can be concluded that, all ages of quails are susceptible for infection with Mycoplasma gallisepticum.