A water-soluble polyester was synthesized from dimethyl octane-1,8-dicarboxylate and polyethylene glycol ((M) over bar(n), = 900). This polymer forms water-soluble inclusion compounds with alpha-, beta- and hydroxypropyl-alpha-cyclodextrin as proven by surface tension measurements, H-1 NMR spectroscopy and titration microcalorimetry. Mainly the octamethylene segments were covered by the cyclodextrins. This inclusion can be used to increase the solubility and the critical micelle concentration of the polyester in water.