It is known that material hardness and surface conditions have a significant impact on the operating life of machine elements working with each other. In this study, Surface roughness values obtained depending on processing conditions and hardness changes on the machined surfaces during milling of AISI 1050 steel were examined. In experimental studies, ideal machining conditions were determined by taking into account surface roughness values and hardness changes using the Taguchi L18 experimental design method. In all experiments, it was observed that the lowest surface hardness was achieved under dry conditions when 6500 1/min speed, 4000 mm/min feed rate, and 0.4 mm cutting depth values were applied. When the speed increased from 5500 1/min to 6000 1/min and the feed rate increased from 4500 mm/min to 5000 mm/min, improvements in surface quality were observed in both machining conditions. In conclusion; In experiments where coolant was applied at high cutting speeds, it was determined that surface hardness and surface roughness values were higher than in dry machining conditions.