Fiber Reinforced Polymer (FRP) is a popular technique that is used to strengthen and repair existing structural elements due to its high strength to weight ratio, fatigue resistance, non-corrosiveness and ease of handling and application at the site. The objective of this research is to study the effect of reinforced concrete (RC) beam and column externally strengthened with glass fiber reinforced polymer (GFRP) sheets after exposing to cyclic wet-dry of water and salt water. The GFRP was applied on tension face of RC beam to improve flexural strength and wrapped around RC column to increase the compressive strength. Then the strengthened specimens were exposed to different exposure conditions such as outside climate, cyclic wet-dry water, cyclic wet-dry sea liked water and cyclic wet-dry sodium sulfate (Na2SO4) solution with duration 1000 hours, 2000 hours and 3000 hours. The result of this experiment showed that the strengthened concrete structure exposed to various exposure conditions FRP could still improve strength. All strengthened RC beam exposed to various exposure condition did not show significant variation compare with unexposed specimens for the same exposure conditions. After exposed for 3000 hours to cyclic water and sodium sulfate (Na2SO4) solution, strengthened RC column start to decrease the ultimate load due to degradation on GFRP strengthening system. The most effect exposure condition is cyclic wet-dry sodium sulfate (Na2SO4) solution.