The removal of gangue minerals from three different graphite ores (Inebolu, Akdagmadeni and Coraklidere) from Turkey by acid leaching was studied. Acid leaching experiments were applied to the flotation bulk concentrates, which were obtained in determined optimum conditions after preliminary flotation tests. The effects of acid type, acid concentration, leaching temperature and leaching time on the dissolution of gangue minerals were studied. The most suitable leaching conditions were determined to be 20% HCl + 4% HF for acid type and concentration, 85 C for leaching temperature and 4 hours for leaching time. After removing the gangue minerals at these optimum conditions, the total carbon contents of the samples from Inebolu, Akdagmadeni and Coraklidere increased from 23.51% to 40.07%, from 37.93 to 60.47% and from 42.28 to 59.47%, respectively.