Ammoniacal leaching and sulfuric acid leaching were explored separately to recover copper from smelter slag. The overall 75% copper recovery was achieved from the smelter slag under optimum condition using ammoniacal leaching. The low copper recovery in this process is directly related to the complex slag mineralogy and dissolution kinetics. To overcome such problems, sulfuric acid leaching was applied separately. This method provided an overall 89% copper recovery under atmospheric condition. The use of sulfuric acid as the leaching agent was found to be more advantageous than ammonia due to the complex interlocking nature of copper bearing particles and different reaction kinetics of the slag.