An inclusion complex of phenytoin (PT) with ${eta}-cyclodextrin;({eta}-CyD)$ in molar ratio of 1 : 1 was prepared, and the interaction between host and guest molecules was confirmed by infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. Suppositories were prepared by the fusion method. PT and $PT-{eta}-CyD$ complex were added to PEG 1540 and Witepsol H-15 under the vigorous stirring at $40^{circ}C$. Content uniformity was tested for different formulations of the PT suppositories. The release rates were dependent on the K.P. V dissolution apparatus and the dialyzing tubing method. Then, the release rates were increased in the following order: $PT-{eta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{eta}-CyD$ complex in Witepsol H-15>PT in Witepsol H-15. The area under the curve and maximum blood concentration after rectal administration were increased in the following order: $PT-{eta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{eta}-CyD$ complex in Witepsol H-15>PT in Witepsol-15.