Laser drilling is one of the earliest applications of lasers in materials processing. Less than 0.25mm in diameter are difficult to drilled mechanically. Laser drilling offers good choices for small hole drilling, especially for hard and brittle materials such as ceramics, but cracks appearance is one of the most difficulties that appears in this drilling. Therefore, this paper aims to study the effect of number of pulses on the drilling of soda lime glass (SLG) using under water laser drilling technique. A 1.15 mm thickness SLG sheets were immersed 1mm below the de-ionized water surface, then irradiated with CW CO2 laser. The laser parameters used were (19, 20.5 and 22) W power, (5, 7.5 and 10) sec exposure time and (2, 3 and 4) pulses. The drilled points were investigated under optical transmission microscope. Then the upper diameter, lower diameter, crack length and taper angle for these drilled holes were measured by analyzing the OM images using ImageJ software. Clearly appeared that hole diameter and the crack lengths could be controlled by the laser power and no. of pulses. When power or pulses were increased, the hole diameter increased. While the length of cracks is decreased with increasing no. of pulses and increased when the power increased. The good results found at laser power 24 W, five sec. and one pulse for hole diameter, while the minimum crack length was found at four pulses, five sec. and 19 W power