Swelling characteristics of expansive soils, namely, swell potential and swelling pressure depend on various parameters such as initial water content, dry unit weight and surcharge pressure. It is important to correctly understand the effect of these parameters on swelling characteristics. This paper discusses the effect of surcharge pressure on swelling characteristics of expansive soils. Swell potential, swelling pressure and rebound were studied of samples subjected to varying initial surcharge pressures. The paper focuses on the need to consider the effect of initial compression on swell potential and swelling pressure. It was found that the actual values of swell potential and swelling pressure obtained when initial compression was considered were higher than the values of swell potential and swelling pressure when initial compression was ignored.