Fire accident is one of the dangerous accidents that could happen to any service structures inrnunexpected times, it could be ignited intentionally to attack enemies among human beingrnaggression, it could be from the result of terrorism attack which of course common nowadays or itrncould be from war among enemies.rnFire accident by its behaviour a little source is enough to be ignited but its costs much to berncontrolled. In our country Ethiopia there were so many lives taking and damaging fire accidentsrnoccurring for instance in the near past an accident caused on TAITU HOTEL in piazza , anrnaccident in Southern Ethiopia, Hawassa demolishing large number of homes and lives.rnA repeated and hazardous fire accidents causing loss of valuable human life, failure of structuresrnand the difficult circumstance to make fire accident under control within a shorter time, increase anrninterest in the design of structures for fire. Now a day there is a good development in usingrnadvanced analytical models to determine fire growth within a compartment and have used finiternelement models of structural components to determine temperatures within a component by heatrntransfer analysis but the experimental way of determining the performance of structural membersrnfor fire is more realistic one.rnThis paper focused in studying the performance of concrete and unrestrained reinforced concreternbeams under fire. In this study different concrete surface temperature and duration of fire exposurernwas considered.rnExperimental investigation on fire performance of concrete and unrestrained reinforced concreternwere carried out and it is discovered compressive strength of concrete reduces up to 30% fromrninitial compressive strength up on exposure to fire causing concrete surface temperature to rise torn246 0c for four hour duration, and residual shear and moment strength of unrestrained reinforcedrnconcrete beam reduce to 80% for 246 0c concrete surface temperature sustained for four hours.rnKey words: Fire duration, Concrete surface temperature, Reinforced concrete beam, Fire rating,rnBending moment capacity, deflection, Shear capacity, Compressive Strength, concrete cube.