Merdey Airport currently serves a type of Cessna 208B Grand Caravan airplane. Due to development phase, the airplane will be replaced by DHC-06 Twin Otter 400 and ATR 42-500 with larger capacity. The airplane replacement is to fulfill the increase number of passengers in the future. The research aims to identify factors affected the length and thickness of runway, analyze the length and thickness of runway needed by the airplane, and also evaluate the existing runway conditions against the analyse results. Analyze is concluded using regulation by ICAO (International Civil Aviation Organization). The results of research showed that the factors affected the length and thickness of runway were the condition at the airport which include elevation, temperature, slope of runway, soil bearing capacity of runway and critical airplane. The length of runway required for the DHC-06 Twin Otter and ATR 42-500 is 470 m and 1.491 m. Then the thickness of pavement required for the DHC-06 Twin Otter and ATR 42-500 is 14,50 inch (36,83 cm) and 16,00 inch (40,64 cm). The existing condition of Merdey Airport has the length of runway 600 m can remain serve the DHC-06 Twin Otter 400 but not for ATR 42- 500. While the existing thickness of runway of 55 cm can serve both of airplane safely.