Sand beach has been widely used at the archipelago as fine aggregate in concrete mixture. Sand beach’s is available in huge quantities in many country side but the quality still needs to be investigated before using in construction. Sand beach can drive to corrosion on the steel reinforcement thus damaging the building. Previous studies have shown that bamboo has good tensile strength and flexural strength. This study aims to examine the use of bamboo as an alternative reinforcement in concrete beam made from sand beach’s as fine aggregate. Sand beach of loto is one of three quarry sources chosen as a fine aggregate in making test specimens reinforced concrete beams as subjected study. Concrete beam specimens consist of 12 beams with 10x15 cm and a length of 120 cm of size. control beam (BN) was made from normal aggregate with steel reinforcement. the Variation of beam specimen (BF1, BF2, BF3, BF4, BF5) was made from sand beach’s fine aggregate with bamboo reinforcement. Bamboo that applied as concrete beam reinforcement was Wulung bamboo kind that have about 3 years of age. bamboo’s tensile test results were obtained average tensile strength is 185 MPa. The flexural test for all beam’s specimen was carried out with two-point loads to determine the amount of deflection that occurs in each beam. Analysis of relations of load-deflection was carried out to each beam specimen from the experiment result. test results showed that the bamboo reinforcement worked as well expected and no splitting occurred, so that the bamboo reinforcement appeared broken when ultimate strength exceeded. The maximum strength was obtained in BF5 beam specimen with an ultimate load 21,5 kN. Flexural test results show that on beams with steel reinforcement tends to occur flexural cracks while on beam with bamboo reinforcement also found shear cracks.