“Shikoko” clay and dredged river sand from Warri, Nigeria were investigated for their use in synthetic sand moulding. Shikoko is a local name for organic clay that dries appreciably to a brownish gray, leather-like consistency. The clay was initially tested for organic matter content, natural water content, particle size distribution, consistency limits and linear shrinkage. The base sand dredged river sand from the same town - was tested for specific gravity, and grain size characteristics. Tests showed that the best mix with the clay was at the binder contents of 13, 17, 33 and 50% of the dry weight of the sand. The synthetic sand mixture was tested for the dry and green compressive strengths, and green permeability. At clay contents of 13 and 17 %, the green and dry compressive strengths of the synthetic mixtures at 5, 10, 15 and 20% moisture contents compared well and were at times higher than the corresponding values for synthetic moulds used in founding. Test results indicated that the synthetic mixture can be used for light casting and in non-ferrous production.