In some areas of the world, bamboo is one of the most widely exploited materials for construction due to the unavailability of limited steel supplies. Replacement of RC and steel by increased usage of bamboo as a building material alternative. This research aims to determine the mechanical strength of concrete reinforced with treated and untreated bamboo sticks as a substitute for steel bars. The materials used were different bamboo species such as Dendrocalamus As per Schultes, Dendrocalamus Merrillianos Elmer, Bambusa Vulgaris Schrader, and Bambusa Blumeana Schultes cut into 60 mm length, and 10 mm diameter bamboo sticks were prepared as primary reinforcements treated with seawater and seawater with mango polyphenol extract treated for 7, days, 14 days, 28days and 56 days based on ASTM standards. The most suitable substitute for steel reinforcement for concrete was the Dendrocalamus Merrillianos Elmer and Dendrocalamus Asper Schultes, which have higher tensile strength when compared to other species. The Reinforced concrete flexural and compressive strength depended on the curing age, the species of bamboo sticks used as reinforcement, and the treatment of bamboo sticks used. Treated bamboo with seawater and mango polyphenol is a suitable replacement for steel bars for concrete reinforcement.