Water-soluble polymers have been used in the last two decades to modify the pharmacokinetics and physicochemical properties of targeted therapeutic agents. Non-invasive imaging techniques such as nuclear imaging can be used to assess the drug delivery efficiency of novel formulations in a cost-effective fashion and thereby facilitate their development process. Polymeric radiopharmaceuticals have also been investigated on their own right as potential nuclear imaging agents. Clinical applications of polymeric radiopharmaceuticals include blood-pool imaging and targeted molecular imaging. In the latter case, water-soluble polymers are often used to modify the pharmacokinetics and biodistribution pattern of ligands that target receptors or antigens at disease sites. As advances are continue to be made in the emerging field of molecular imaging, nuclear imaging will play an increasingly important role in the development of polymeric drug delivery systems. Similarly, polymer technology will also be integrated into the development of molecularly targeted radiopharmaceuticals. Here, we review various aspects of polymeric radiotracers and their applications in nuclear imaging.