Hydrocortisone (HC) sustained-release suppositories were prepared by using a solid matrix of methacrylic acid-methacrylic acid methyl ester copolymer $(Eudragit;L_{100}^{R}:;EL)$ as a poorly water soluble carrier and polyethylene glycole 1540 (PEG) as an water soluble carrier. HC release rate was controlled by complexation with ${eta}-cyclodextrin$ $({eta}-CyD)$ which was confirmed by X-ray diffractometry, IR-spectroscopy and differential scanning calorimetry. Release rate of HC from the EL-PEG matrix suppositories decreased with increase of EL contents. The release rale from $HC-{eta}-CyD$ complex decreased in the following order: $HC-{eta}-CyD/PEG$ > HC/PEG > $HC-{eta}-CyD/EL_{10%}-PEG$ > $HC/EL_{10%}-PEG$ > $HC-{eta}-CyD/EL_{15%}-PEG$ > $HC/EL_{15%}-PEG$ > $HC-{eta}-CyD/EL_{20%}-PEG$ > $HC/EL_{20%}-PEG$. The crystallinity of HC in polymer matrix was identified using X-ray diffractometer and the surface of matrix suppositories after release test was examined by scanning electron microscopy. The sustained release of HC from these matrix suppositories was attributed to the network structure of EL.