The aim of the research work is to presents the result of experimental studies concerning the flexural behavior of post tensioned geopolymer concrete beams. In this study the flyash based geopolymer concrete mix design was obtained for M50 grade. The fluid to flyash ratio was fixed as 0.45. The ratio of sodium silicate to sodium hydroxide was 2.5 and the concentration of the solution is 14 molar. The preliminary tests were carried out for the geopolymer concrete and conventional concrete and optimizing the mix design. A total of four beams of size 125 × 250 × 3200 mm were cast and tested in the laboratory. Of which two of them are geopolymer concrete and the remaining two beams are conventional concrete. All the beams were tested under static monotonic loading and the results were presented. Comparison was made between conventional concrete and geopolymer concrete.