An attempt was made in this study to analyze volatile flavor components of fresh and odorless garlic (Allium sativum L.), Essential oils in fresh garlic and odorless garlic were isolated by a simultaneous steam distillation and extraction(SDE) method using n-pentane/diethy ether as solvent. A total of 21 and 22 components were identified by GC/MS from the essential oils of fresh garlic and odorless garlic, respectively. Diallyl trisulfide, diallyl disulfide and methyl allyl disulfide were found to be major volatile flavor components in fresh garlic and odorless garlic. By the preparation of ordorless garlic, 77.5% of diallyl trisulfide, 15.0% of diallyl disulfde, 72% of methyl allyl disulfide, and 78.4% of allyl thiol components in fresh garlic were lost. Eleven compounds including 2-vinyl-4H-1,3-dithiin, eugenol and 2-methoxy-4-vinyl-phenol were identified in odorless garlic, but not m fresh garlic.