The thermodynamics of binding was determined for soybean glycinin and β-conglycinin and flavor ligands butanal, pentanal, hexanal, octanal, 2- and 3-hexanone, 2- and 5-nonanone, hexanol, and hexane. Hexane had affinity for these proteins only at 5oC. Affinities of binding for all flavor ligands were greater for glycinin than β-conglycinin. Affinity for aldehydes increased with increasing chain length for glycinin, but remained constant for β-conglycinin. ΔGo, ΔHo, and ΔSo for binding were determined. ΔGo was negative for all ligands and ranged from −1.74 to −4.16 Kcal/mol. All enthalpies of binding were positive except butanal and hexanol. Change in free energy of binding per CH2 in homologous aldehydes was greater for glycinin than β-conglycinin.