SMAW welding is one type of welding that is often used. The purpose of this study was to determine the effect of welding current on welding joints, with variations in current used 100 A, 120 A, and 130 A, on tensile strength, impact and microstructure on ST37 steel. From the research results obtained the highest average value of tensile strength with a current variation of 100A, amounting to 444.3 MPa. The highest average value of elongation was obtained at 120 A with a value of 37.66 %. The highest average value of elastic modulus is obtained by the current variation of 100 A with a value of 1234.70 MPa. In the impact test, the highest average value of the 100 A current variation with a value of 47 joules. The conclusion of this study is that a welding current of 100 A provides optimal results in terms of tensile strength, toughness and microstructure characteristics in ST37 steel welding joints with the SMAW welding process.