This study was conducted at Horticulture Department of Cukurova University, Adana, Turkey, during 2011-2012 years to determine volatile aroma compounds of Agaricus bisporus and the most useful extraction technique. Agaricus bisporus is one of the commonly consumed and cultivated edible mushrooms all over the world. Edible mushrooms are consumed for their taste and aroma as well as nutritional characteristics. Therefore, aroma studies on mushrooms are very important. Fresh sample of Agaricus bisporus (Sylvan A15 variety) obtained from Mega Tesnim Mushroom Company, Turkey, was used as material. Volatile aroma compounds were performed by Headspace Gas Chromatography Mass Spectrometry (HSGC/MS). Three different extraction methods were examined. Extraction was done at 35 degrees C (Extraction Method 1), 50 degrees C (Extraction Method 2) and 60 degrees C (Extraction Method 3) using heated magnetic stirrer and duration was 20 min. Experiment results showed that EM2 was the most useful method for determining aroma compounds of Agaricus bisporus, 15, 21 and 8 different aroma components were identified through EM1, EM2 and EM3 extraction methods, respectively. Alcohols, acids, ketones, esters, phenol, 2-heptanamine; 2-octanamine; 1,3-benzenediamine, 4-methyl; isopropyl myristinate; 6-chloro-11,11-dimethyl-10,11-dihydro-7, 10-epoxy-7H-cyclohepta [d]-1, 2,4-triazolo [4,3-b] pyridazine; N,N,4-trimethyl-benzene-sulfonamide; 2-methylpyrazolo; 3-(perhydro-1, 4, 2-oxain-4-yl) carbonylpyridine; cis,trans-2, 2'-(1,2-phenylenedivinylene) difuran; benzene and butyroin were determined. 1-Octen-3-ol was found to be the major aroma compound through EM1 and EM2 extraction method at levels of 62.93% and 39.04%, respectively. 2H-Benzimidazol-2-one was identified tobe the major component through EM3 extraction method.