In this paper, the test results such as index properties, Proctors compaction, swelling and unconfined compression strength obtained on expansive clays mixed at different proportions of fly ash and stone dust are presented and discussed. From the results, it is observed that at optimum percentages, i.e., 30% stone dust and 25% fly ash, it is found that the swelling of expansive clay is almost controlled and also noticed that there is a marked improvement in the strength of soil. The combination of stone dust and fly ash is more effective than the addition of stone dust alone to the expansive soil in controlling the swelling nature. The combination of 20% stone dust and 25% fly ash addition at the optimum moisture content to the expansive soil is found to be a suitable measure to reduce the swelling and increase the strength of the two expansive soils tested.