Differential scanning calorimetry was applied for an analysis of the cogrinding-induced crystallinity changes of naproxen in binary mixtures with linear maltooligomers. Factors found to play a role in the amorphization process were the mixture composition, the duration of mechanical treatment and the degree of polymerization of the carrier. Maltopentaose was about as active as amorphous hydroxypropyl α- and β-cyclodextrin MS 0.6, while maltotetraose displayed practically the same amorphizing capacity as those of native α- and β-cyclodextrin. The melting peak temperature of naproxen was substantially unaltered by cogrinding with maltooligomers, whereas it was considerably lower in coground mixtures with cyclodextrin derivatives. This might be due to the formation of a true inclusion complex in the solid state.