Abstract: The study investigates the natural frequency of sandwich plates made from stainless steel and Teflon with crack effect. The fundamental natural frequencies are analyzed experimentally by impact hammer and numerically by ANSYS 15. The aim of the experimental investigation is the fabrication of the sandwich plate made from (stainless steel/ Teflon/stainless steel). Then 2 mm width cracks are created using Ferton power tool with 330 W and 10,000-32,000 rpm. The length of the formed cracks having 20-40 mm lengths located in different location with angles 0, 30^°, 45^°, 60^° and 90^° angle, respectively. The mechanical properties of Teflon and stainless steel such as young modulus and density are estimated. Then the fundamental natural frequencies of a clamped cracked sandwich are measured. The existence of a crack in the sandwich plate decreases the natural frequency of plate depending on the size, location and orientation angle of the crack. The experimental and numerical natural frequency results show that maximum value occurred in 20 mm central crack rotated by 45 while the minimum value occurred at 40 mm central horizontal crack. There is a considerable match between the results of the experimental and the ANSYS package investigations with a percentage error ranged between 4.04-7.19%.