A study was undertaken to assess the effects of level of grass mulch on soil water retention and performance of cowpeas (Vigna sinensis (L.) Savi ex Hassk.) and eggplants (Solanum melongena L.) grown on a Fitches clay soil in Antigua, West Indies. Dried guinea grass (Panicum maximum L.) was applied as a surface mulch at rates of 0, 2, 4 and 8 t ha-1. Each treatment was replicated four times, under tilled and non-tilled conditions, in a randomized complete block design. The results show that the mulched soil conserves more moisture within the profile than unmulched soil, particularly in the surface soil. The higher water content of surface soil had a positive effect on the germination of cowpea seeds. The mulch suppressed weed growth within both cowpeas and eggplants, but the effect was most pronounced in crops grown under tilled conditions with the heaviest mulch rates (4 and 8 t ha-1). Yield of both crops, in terms of the accumulation of dry matter in cowpeas and marketable yield of eggplants, was positively affected by mulching. This study indicated that the optimal mulch rate for soil water retention, seedling emergence, weed control and yield of both crops was 4 t ha-1 dried guinea grass under Antigua conditions.