The inclusion complex of capric (C-10) and caprilic (C-8) acids with beta- and gamma -cyclodextrins (CDs) was analyzed, in the solid state, by differential scanning calorimetry (DSC), thermogravimetry (TGA), and infrared spectroscopy (FT-IR). Special attention was paid to the acid behavior in terms of the quantity incorporated and the thermal stability. The results showed that the maximum amount of incorporated acid in beta -CD occurred at molar ratio (CD:acid) of 1:1 and 1:1.5 for C-10 and C-8, respectively. For the same acids in gamma -CD, the proportions increased to 1:1.5 (C-10) and 1:2 (C-8) The heat for the water volatilization was higher in gamma -CD (ca. 91 cal g(-1)) than beta -CD (ca. 52 cal g(-1)) systems, for both acids, probably because of the high cavity size of gamma -CD. Although, both systems improved additional thermal stability with the complex formation, the acids acquired a higher thermal stability in the beta -CD inclusion complex.