This paper evaluates the effect of heat on the compressive strength of concrete by way of comparing the strength of concrete that was subjected to heat treatment with unheated one. Concrete ingredients available locally were obtained for the production of cubes into a dimension of 15x15x15 cm. A total of 12 cubes were cast and then cured at room temperature (28 ?C). The cubes were divided into four sets. Each set comprised of 3 cubes for each Water-Cement ratio. Two of these sets were cured for 14 and 28-day out of which one set each was heated at a temperature of 200oc for about 4 hours. They were then crushed subsequently to compare their strength. The results revealed that at the 14-day curing, the average compressive strength of unheated cubes was 19.4N/mm2 for heated cubes and 17.4N/mm2 for unheated ones. While at 28-day crushing, the average strength for unheated and heated cubes was 25.8N/mm2 and 23.3N/mm2 respectively. In both cases, the difference in strength is between 2N/mm2 and 2.5N/mm2 which is significant and can have a practical impact.The conclusion was drawn from the results obtained that the strength of concrete decreases as it is exposed to high temperature.