Theranostics aims to create a single entity that can detect and treat disease, as well as measure disease and therapeutic progression. This is commonly achieved by the incorporation of molecular imaging reporters, therapeutic agents, and targeting moieties into a single nanomaterial. Hyperbranched polymers have been successfully developed into theranostics owing to the high diversity of functionality that can be introduced through the distinct chemistries of their chain ends, branch points, and sidechains. In this protocol, we introduce the straightforward synthesis and characterization of biocompatible hyperbranched polymers for use as molecular imaging agents and theranostics. We detail a broad range of orthogonal chemistries that have been proven for introducing fluorophores, positron emission tomography (PET) radioisotope chelators, targeting agents, and therapeutics, at precise locations within the polymer structure. We also outline methods for using fluorescence and PET imaging for the preclinical evaluation of new hyperbranched polymer theranostics. These protocols will enable the application of these well-understood polymer materials in new disease applications and models.