THIS RESEARCH AN ATTEMPT TO INVESTIGATE THE KINDS OF blocking SYSTEMS OVER ATLANTIC AND PACIFIC OCEANS AS SYNOPTIC AND INTRODUCE; ALSO ATTEMPTS TO INVESTIGATE CYCLOGENESIS PHENOMENA OVER MEDITERRANEAN SEA, AND SPECIALLY IN THE EAST OF MEDITERRANEAN SEA, THAT THEIR EFFECTS INFLUENCE OVER IRAN'S REGION. AT THE FIRST STEP OF STUDY, MEDITERRANEAN TOPOGRAPHY, LOCAL MEDITERRANEAN WINDS AND CYCLOGENESIS HAVE STUDIED; THEN STRUCTURE AND TYPES OF EXISTING blocking SYSTEMS ON SYNOPTIC WEATHER MAPS HAVE INTRODUCED WITH FIGURES.