The dry density and shear strength of Iwo (Alfisols), Egbeda (Entisols) and Ondo (Ultisols) soil series in south-western Nigeria were measured at different compaction efforts and moisture contents. Results indicate that dry density and shear strength increased considerably with increase in compactive effort (P < 0.05). Maximum values of dry density were reached at predetermined critical moisture content for compacting the soils, while the strength decreased continuously with increasing moisture content. Superimposing the two curves of dry density and shear strength versus moisture content, respectively, gave the best compromise moisture content for trafficability of the soils. Regression equations were derived to relate the equilibrium moisture content for trafficability of the soils to soil components and dry density.