Several experimental researches have been studied the effect of impinging jet on horizontal cylinder cooling whether the impinging jet is fixed or rotating. Very few studies have been investigated the effect of surface roughness in the quenching process. The current study focused on making a comparison of the cooling characteristics between smooth and roughened horizontal stainless-steel cylinders. The cooling characteristics have been studied taking into consideration different parameters as specimen initial temperature from 250 to 450°C, coolant temperature from 40 to 80°C, number of impinging jets from 1 to 3, effect of coolant velocity from 2.5 to 6 m/s and surface roughness which has been used two different types of surface roughness The first type fabricated by using laser cutting machine used to roughening the specimen. The second type fabricated by making narrow groove channels in the specimen with width 2 mm and 30 apart from each other.