The present work was designed to study the relation between the rate of strangles infection in equine and seasonal incidence in Cairo and Giza governorates, beside the isolation and identification of Streptococcus equi. Seventyeight horses of different ages have been studied for S.equiinfection along the period lasted between January 2014 and December 2015. The most frequent clinical symptoms was the nasal discharge (100%), then signs like abscess formation and fever have been presented by 71.8% and 33.3% respectively. Most of clinical cases have been detected in age of six to twelve months (71.15%). Most of strangles-positive cases have recorded in winter season (60.03%) followed by spring (20%) and summer (18%). According to the biochemical results 75% of clinical cases caused by S. equi followed by S. zooepidemicus.S. equiinfection has been confirmed by the PCR technology through detection of Sod A gene.