Activity coefficients at infinite dilution in water have been determined for some aroma compounds detected in brown crab liquid effluent produced during boiling (1-octen-3-ol, 1-penten-3-ol, 3-methylbutanal, hexanal, benzaldehyde, 2,3-pentadione, and ethyl acetate) by using the headspace gas chromatography technique (HSGC). Experimental data have been obtained over the temperature range of (40 to 50) °C. In this work, activity coefficients at infinite dilution for different kinds of systems have been considered: one component solute + water and multicomponent solute + water. No significant differences were observed between activity coefficients obtained in these two kinds of systems. Additionally the effect of salt concentration at 40 °C has been studied by varying the salt concentration from (0 to 1.71) mol·kg−1. Experimental data were fitted as a function of salt concentration by using the Setschenow equation, obtaining the salting-out coefficient. ; MICINN through CTQ2008-04999-PPQ