Temperature-dependent polymers are intelligent materials In this study, biocompatible and temperature-dependent hyperbranched poly(glycidol)s (HPGs) were synthesized and characterized HPGs were succinylated then modified with the oligo(ethylene glycol) monoethers (OEG) for example methoxy di(ethylene glycol), methoxy tri(ethylene glycol), methoxy tetra(ethylene glycol), ethoxy di(ethylene glycol), ethoxy tri(ethylene glycol), and methoxy poly(ethylene glycol)s at different ratios These polymers exhibited phase transitions at a specific temperature (the cloud point), depending on the composition of OEG. By tuning the composition of OEG in the polymer, thermosensitive polymers with cloud point near body temperature were produced Endothermic peaks of these polymers were observed in the vicinity of the cloud point It is suggested that at temperatures below the cloud point the polymers formed hydrophobic shells and became more hydrophobic at temperatures above the cloud point Because they exhibited no cytotoxicity, these temperature-sensitive polymers are useful for biomedical applications. (C) 2010 Wiley Periodicals, Inc J Polym Sci Part A Polym Chem 48 4047-4054, 2010