Although, the disease has been controlled successfully in many parts of the world by regular vaccination of susceptible animals and slaughtering of infected animals, no country has been considered safe, because of the highly contagious nature and rapid spread of the infection for the effective control of the disease, outbreaks should be detected at an early stage and persistent infections should also be recognized to prevent further transmittance. The purpose of this study was to determine the virus strain that caused FMD in cattle of Basrah marshes by amplified VP3gene in seven strains of FMDV deposited in the Gen Bank database. The results revealed that the O strain type was appear in a total of cases (100%) of the virus strain that caused foot and mouth disease in cattle of Basrah marshes by amplified VP3gene from seven serotype of FMDV. From the total cases 8% were ASIA1 serotype , 4% SAT1, 2% SAT2, while the other strains A, C and EUR were 0% . The results showed interaction among the strains in appearance of FMD, the interaction between O and ASIA1strain was 7%; O and SAT1 was 4%; O and SAT2 was 2%; O, ASIA1 and SAT1 were 4%; O, ASIA1 and SAT2 were 2%; O, ASIA1, SAT1 and SAT2 were 2%. The interaction between ASIA1 and SAT1 was 4%; ASIA1 and SAT2 was 2%; ASIA1 , SAT1 and SAT2 were 2%.