Raw red mullet (Mullus barbatus) and its cooked samples, obtained from steam and oven cooking, were subjected to aroma and key odorant analysis for the first time using GC-MS-O. The extraction of the aroma compounds was carried out by the direct solvent extraction solvent assisted flavor evaporation (DSE-SAFE) method. Principal component analysis (PCA) was used to determine the relations between cooking processes and fish aroma compounds. By applying the aroma extract dilution analysis (AEDA), 8 and 13 aroma-active compounds were detected in raw and cooked fish samples, respectively. The most prominent differences between raw and cooked fish samples were as follows: 3-hydroxybutan-2-one, 2,3-octadienone, (E,E)-2,4-heptadienal, linalool, gamma-butyrolactone, 1-methylpyrrolidin-2-one, 2H-furan-5-one and pyrrolidin-2-one were only detected in cooked samples while hexanal and 2-phenoxyethanol in only raw fish samples. GC-MS-O results clearly indicated that cooking process results in the development of characteristics and pleasant aroma of red mullet samples due to the lipid oxidation. The most dominant aroma-active compound in the cooked fish samples was the 1-octen-3-ol which is responsible for the mushroom-like odor.