THE PRESENT RESEARCH INVESTIGATES THE EFFECT OF IRREGULAR WAVES ON SIZE OF WAVES’ REFLECTION FROM RESHAPING RUBBLE MOUND BREAKWATERS. THE SHAPEABLE RUBBLE MOUND BREAKWATER IS A TYPE OF BREAKWATER WHICH ITS PRELIMINARY PROFILE CHANGES BY WAVES STRIKE. THE PRESENT RESEARCH IS DONE USING THE LABORATORY MODELING METHOD IN WAVE FLUME. THE WAVES RADIATED TO THE MODEL OF BREAKWATER SECTION WERE IRREGULAR AND WITH JONSWAP ENERGY SPECTRUM. TO INVESTIGATE THE EFFECT OF WAVES’ CHARACTERISTICS ON THE WAVE REFLECTION SIZE, THE UNBROKEN, FRAGILE AND BROKEN WAVES WERE APPLIED. THE LIMITATION OF WAVES’ HEIGHT WAS CONSIDERED 4 TO 14 CENTIMETER, AND THE AVERAGE PERIOD WAS BETWEEN 0.9 TO 1.7 SECOND IN LABORATORY. TO IMPLEMENT THE MATERIAL OF ARMOUR LAYER, STONE GRADING OF 1.82, 1.44, AND 1.14 WERE APPLIED. TO INVESTIGATE THE EFFECT OF STRUCTURE SLOPE, THE SLOPES OF 1:1.25, 1:2, 1:2.5 WERE TESTED WITH SCALE OF 1:50. TO INVESTIGATE THE EFFECT OF SCALE, SOME INDEX TESTS WERE REPEATED WITH SCALE OF 1:30. THE NUMBER OF WAVES’ RADIATED TO THE MODEL STRUCTURE WERE CONSIDERED 1000 TO 6000 AND TOTALLY 120 TESTS WERE DONE. THE LABORATORY RESULTS ARE PRESENTED WITH GRAPHS AND COEFFICIENT RELATIONS AND USING THE REGRESSION METHODS AND THE NEW FORMULAS ARE GIVEN TO THE LABORATORY DATA WHICH ARE ALSO PRESENTED IN THIS ARTICLE.