The solid state stability of a series of beta-cyclodextrin/alkylcobaloxime inclusion complexes has been investigated by differential scanning calorimetery (DSC) and thermogravimetric analysis (TGA). Four distinct transitions in the TGA scans, corresponding to dehydration (Tc1), dealkylation (Tc2), breakdown of equatorial oxime ligands (Tc3), and decomposition of beta-CD (Tc4) were generally seen. Three distinct transitions during DSC, corresponding to Tc1 (endotherm), Tc2 (exotherm) and Tc4 (endotherm), were observed in most cases. In addition, the temperatures of dealkylation were higher in beta-cyclodextrin/alkylcobaloxime complexes than those of the corresponding alkylcobaloximes. The Tc2 changes were related to the substitution groups on the alkylcobaloximes and paralleled the stability constants of these inclusion complexes.