Concrete is a composite material of which 60-75% by volume is aggregates. Out of this rnvolume, 30-40% is composed of fine aggregates. Fine aggregate is one of the predominant rncontents of concrete usually natural river sand is used as the fine aggregate. Wanza Sawdust rnwhich is the byproduct Wanza wood is abundantly available in Tepi, Ethiopia. However, rnthere is no sand source in Tepi, Ethiopia. Therefore, this research tried to study the possibility rnof sawdust to replace sand in the production of concrete. rnThe objective of this experimental study was to investigate the effect of using sawdust as an rnalternative for fine aggregate in concrete production and by determining the optimum rnreplacement of sand with sawdust that can be acceptable for the production of concrete. The rnresearch studied workability, setting time, density, compressive strength and water rnPenetration of C-20 class of concrete produced by replacing 5%, 10%, 15%, 20% and 25% by rnvolume of sand with sawdust. rnIn studying the properties of concretes, a total of twelve concrete mixes made with OPC and rnPPC were prepared by replacing sand with sawdust. The investigation of this thesis has rnrevealed that compressive strengths of OPC concrete mixes with 5%, 10% and 15% sand rnwith sawdust replacement satisfy the 20MPa cube Compressive strength compliance criteria rnof ACI 301, Specifications for Structural Concrete, at 28 days. The strengths achieved, 21.4, rn20.8 and 20.2MPa respectively, are greater than the specified .At 56 days the compressive rnstrengths of PPC concrete mixes with 5%, 10% and 15% sawdust replacement satisfy the rncompliance criteria of ACI 301. The strengths achieved, 21.8MPa, 20.8MPa and 20.4MPa rnrespectively, are greater than the specified. rnSawdust retarded the hydration reaction of cement because the setting time of concrete rnincreased when percentage replacement of sand with sawdust increased. The slump of the rnconcrete decreased through percentage replacement of sand with sawdust and also the density of concrete decreased with the percentage replacement of sand with sawdust. The water rnpermeability of concrete increased through percentage replacement of sand with sawdust. rnFinally, based on 15% optimum replacement of sand with sawdust, the material cost of rnconcrete with sawdust was found lower than concrete without sawdust. In one meter cube, the rncost of concrete made with sawdust decreased by 49.8 birr or 3.78% than concrete without rnsawdust.