The heat treatment and corrosion of aluminum 6063 alloy was investigated. The aim of this work was to determine the effect of heat treatment on the microstructure and the corrosion of aluminum 6063 alloy using weight loss method. The samples conditions were; as-cast, solution treated, supersaturated and age hardened condition. They were soaked in a 10 molar solution of sulphuric acid and monitored with time. The corrosion rate was calculated for various immersion periods. The result shows that the corrosion rate of the alloy was due to the nature of heat treatment given to the samples. Similarly, it was also found that the corrosion rate of the Al(6063) alloy was higher in the as-cast sample compared to the heat treated alloy. The passivation on the heat treated Al(6063) alloy was a little more stable therefore reducing the corrosion rate after 35 days of immersion for the aged hardened samples.