This study aimed to detect Mycoplasma gallisepticum (MG) strains in chicken flocks in Egypt with respiratory disease. Nasal swabs from 49 flocks were tested by semi-nested PCR and restriction fragment length polymorphism (RFLP) of the pvpA gene. MG was detected in 37 flocks (75.5% incidence). RFLP analysis identified genetic similarity between some field isolates and the F vaccine strain. Experimental infection of chickens found that field isolates and the F strain were transmitted between infected and contact birds based on PCR testing, with some contact birds developing antibodies. This highlights the need for improved diagnostics and control of MG variant strains.