Steel slag is an industrial waste that can be used by Civil Engineers rather than it constituting a nuisance to the environment. The suitability of a lateritic soil for use as a subgrade, subbase or base course material, after adding some percent of steel slag, was checked from the results of sieve analysis, specific gravity, Atterberg's limits, compaction, California Bearing Ratio (CBR), unconfined compression and permeability tests.