This work investigates the suitability of a composite material (palm kernel shells-rice husks), as substitute to granite in concrete based on the compressive strength and workability of concrete. The aggregates were batched by volume in a ratio of 1:2:3, and water-cement (w/c) of 0.5. The percentage replacement of aggregates by palm kernel shells-rice husks composite was varied from 0% to 100% at intervals of 25%. The slump test was used to determine the workability of the fresh concrete. The compressive strengths of cured concrete cubes of sizes, 150mmx150mmx150mm were determined at 7days (2.74 N/mm²), 14days (5.93 N/mm²), 21days (7.63 N/mm²) and 28days (9.18 N/mm²) respectively. The result showed that the composite mix of P₇₅R₂₅ at 28-day curing period produced the best value of compressive strength 9.18N/mm². Thus, the result obtained from this study revealed that replacement of granite aggregate in concrete making with composite material of palm kernel shells and rice husks in batched volume proportion of 1 part of cement to 2 parts of sand to 3 parts of composite materials is adequate for construction of farm buildings when compared with normal weight aggregate one.