Waste foundry sand is generated by the metal casting industry and has great potential to be used as a construction material. Nearly 70 % of the waste foundry generated is disposed of as a landfill which poses a threat to the surrounding environment. The negative impact of landfill disposal of waste foundry sand on the environment has invited the intentions of research faculty. In this research work, the impact of waste foundry sand as sand replacement on the properties of concrete cured in water as well as sulfate solution were explored. Test results indicate that the compressive strength of concrete cured in sulfate solution decreases with the use of waste foundry sand as partial substitution of natural sand. However, a chloride ion penetration resistance of concrete hikes on the accumulation of waste foundry sand. Up to 56 days, a concrete mixture made up of 15 % waste foundry sand showed optimum strength properties. Ultrasonic pulse velocities through concrete mixtures cured either in water or sulfate solution were almost identical. Energy dispersive spectroscopy analysis showed traces of sulfur in concrete mixtures cured in a sulfate solution.