The Defence and Aviation Clustering idea at Ostim has actually emerged after the study made with the International Competitiveness Research Institute (URAK) in 2007 to perceive that Ostim Organized Industrial Zone (Ostim OSB) is competitive at which sector and to what extent.This analysis has shown that Ostimincorporates sub-industry which is needed by defence and aviation industry in terms of machining, sheet forming, surface treating, electro mechanics, composite and cabling. The companies currently performing activities in these fields were delivering services to main industry companies located at Ankara. For this reason, we can say that a natural clustering was available at Ostim.