The effect of beta-cyclodextrin (beta-CD) on the release of naproxen (1) from fatty suppository bases was investigated. The solid complexes of 1 with beta-CD in a molar ratio of 1:1 were prepared by using the kneading, co-precipitation and grinding method. Witepsol(R) H15 and Massa Estarinum B suppositories were prepared, containing the intact 1 and 1-beta-CD complex, respectively. The in vitro release of 1 from fatty bases was examined. The release data were assessed kinetically. The best fit was obtained with Q vs. the square root of time.