Foot-and-mouth disease (FMD) is an endemic disease in Egypt and most parts of Africa causing huge economic losses. Control of FMD using vaccination requires information on the occurrence of various FMDV serotypes. This study aimed to determine FMDV serotypes in QalyobiaGovernorate, Egypt. A total number of 21field samples from different localities, were collected from buffaloes at age of 6monthes to 3 years during 2017. Field samples have been screened for FMDV detection byr.RT-PCR using universal primers and were further subtyped using serotype-specific primers. The r.RT-PCR screening revealed that 9 samples out of 21 were positive for FMDV serotype O.9 samples were propagated on BHK-21 cell line for 3 passages revealing cytopathic effect (CPE) in the form of cell rounding and aggregations in all 9 samples. Virus neutralization test was applied on positive isolates using anti FMDV serotype O and the results confirmed that these isolates were FMDV serotype O. On the other hand,histopathological finding showed that lung was congested, emphysematous multiblealveoli with accumulation of serofibrinous exudate. The tongue exhibited multiple foci of vesicular degeneration with serous exudate and inflammatory cells. The heart showed severe zenkers necrosis with mononuclear inflammatory cells infiltration and edema. The kidney revealed swollen endothelial cell lining blood vessels with some degenerative changes and most renal tubules showing degenerative changes.Bloodvessels in most organs showed severe vasculitis.Immuno peroxidase technique was done on paraffin sections showed marked strong immunopositivity reaction in basal and prickle cell layer. Therefore, control efforts should focus on reducing the circulation of FMDV among susceptible livestock with special attention towards water buffaloes.