Recent advances in polymer chemistry have led to the development of novel materials with both controlled functionality and structure resulting in unusual rheological properties. Examples include the many di- and triblock copolymer architectures and dendritic systems. These materials often include regions of different polarity and hydrophobicity and therefore represent a challenge to the analytical chemist. This application note illustrates the analysis of a star-branched polyethylene glycol with a significant hydrophobic component by aqueous SEC.