The volatile flavor components of snow crabs from the Young-duk coast of Korea and their concentrated cooker effluent were isolated by a modified method from Likens and Nickerson, using a simultaneous distillation and extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-MS. The flavor profile of boiled crab demonstrated that the favorable flavor characteristic of crab involved a seafood-like note, and that of concentrated cooker effluent demonstrated that the weak boiled crab flavor involved a fishy note. The main flavor components of boiled crab were heterocyclic compounds including alkylpyrazines, thizoles and thiolanes, aliphatic ketones including 2-heptanone and nonanone. On the other hand, the main flavor components of cooker effluent were aldehydes including 3-methylbutanal, alipatic ketones including 2-heptanone and alkanes including 2,6,10,14-tetramethyl-pentadecane. Almost all of heterocyclic compounds, which seem to be important contributors to the flavor of boiled crab, were not identified in concentrated cooker effluent. As a result, there may be a need to add the crab flavor components formed through model experiments of Maillard reactions to the concentrated cooker effluent for human consumption.