Abstract Shielded metal arc welding is the most general purpose and popular welding process. Current of welding is the main controlling factor for the properties of welded product. Hardness of the product is generally required property while in work which depends upon the chemical composition of the product. The main purpose of this research work was to investigate the effect of welding current and process of cooling on hardness and chemical composition of the weld of mild steel utilizing shielded metal arc welding process. Three pairs of mild steel plates were welded using shielded metal arc welding process at currents of 90 A, 100 A and 110 A respectively having other variables like voltage, speed of welding and feed rate etc. as constant and cooled in water of normal temperature 300 C. Similarly three other pairs of mild steel plates were welded at the said input values and cooled in normal air. The hardness values and chemical composition of base metal, heat affected zones and welded zones were recorded in all the cases and it was found that the heat affected zone has more hardness than the base metal but the weld zone has the maximum hardness. The percentage of Carbon was also found to affect the hardness of the material.