The most use of laser in industries is Laser cutting. This method of cutting is a thermal process that uses a focused laser beam to melt the material locally. The melt is then blown out of the kerf with a high pressure gas jet that flows in a cutting nozzle. Comparing with the conventional cuttig methods, the heat affected zone, thermal distortion and kerf width is much lower and resulting better cutting quality. In this research thin sheets steel laser cutting has been investigated experimentally. For this goal the preparation of laser cutting equipments for CO 2 laser at IUT Laser Optic lab was done. In addition designing and manufacturing of cutting nozzle have been acomplished. In the next step the effect of a number of process parameter on the cutting quality has been studied. Cutting speed, oxygen pressure, laser power and stand-off distance have been considered as input parameters and the thickness of heat affected zone, kerf width and surface roughness have been considered for studding the cutting quality as output parameter. The taguchi method with orthogonal arrey of L 9 and L 27 was applied to investigate the effect of the input parameters on the output parameters at the same time and optimize them. It has been found most effevtive parameters on the process are Cutting speed, oxygen pressure and laser power respectively. The study also showed that the stand-off distance has very low influenc on the cutting quality. Furtheremore, it was shown that the best cutting quality was achieved at the highest cutting speed within the studied ranges of parameters.The result indicate that there is an optimum range for the oxygen pressure in which the smallest thickness of heat affected zone and the lowest value of roughness was achieved at 4.5 bar gas pressure. Excessive heat input that cuases side burning and instability of the melt pool at higher appleid gas pressure are responsible for increasing the thickness of heat affected zon and roughing the cutting face. Also there is an optimum range for laser power to achieve the lowest roughness of cutting face. The surface roughness increases with increasing the stand-off distance. Laser cuttting of the different steel sheet thicknesses showed that the used low power CO 2 is capable to cut the sheet with 1.2 mm thickness with appropriate cutting speed of 1.5 meter per minute. In addition, the kerf width and the heat affected zone measured to be less than 140 micron and 100 micron respectively. Keywords: Laser cutting, CW CO 2 laser, Kerf width, Heat affected zone, Surface roughness