Twenty two Mycoplasma isolates were recovered from 120 coturuix quilas at Isamilia governorate. Identification and serotyping of these isolates revealed 9 M. gallisepticum (MG), 8 M. gallinarum and 5 M. pullorum. Experimental infection was designed where 10 chicks (one week old) were inoculated intranasally with 0.2ml  10⁷ CFU/ml M. gallisepticum isolated from  quails, 10 chicks were inoculated with M. gallisepticum S6 strain and 10 chicks were considered as control negative. Post mortem (PM) lesions were milder in chicks inoculated with M. gallisepticum isolated from quail compared th those inoculated with M. gallisepticum S6 strain and presented by congested lungs and liver, turbidity, and thickening of air sacs. Histopathological examination showed that the lungs of chick infected with M. gallisepticum isolated from quail showed oedema with mononuclear leucitic inflammatory cells infiltration in the interlobular connective tissue stroma.The grade of histopathological examination of tracheas of chicks infecte with M.G. isolated from quail showed local lymphoid cell aggregation of leucocytic inflammatory cells in the lamina propria underneath the epithelial mucosa was mild. Mycoplasma gallisepticum could be reisolated and identified from challenged. Serologic antibody response was less in sera of chicks infected with M. gallisepticum isolated from quails. Polymrase chain reaction confirmed that the Mycoplasma isolated were M. gallisepticum.