Abstract <p>3D bioprinting is the additive manufacturing technique in which the biomaterials are printed in a layer-by-layer fraction. Inkjet bioprinters, laser bioprinters, and extrusion-based bioprinters are the major types of bioprinters that are commercially available. For any of the bioprinters, the biomaterial selected for printing is very important. Hydrogels are the widely used biomaterials for bioprinting because of their biocompatible nature. They are made from polymers of natural or synthetic origin. These polymers can also be used as composites. Once the hydrogel is developed, it must be characterized to ensure that it has all the properties of printable biomaterials. The characterization of biomaterials is done mainly based on the ISO10993 standard. According to the standard, the biomaterials must be characterized for their physicochemical, mechanical, and biological properties. After characterizing and ensuring that the selected material is having all the desired properties of a printable biomaterial, it can be used further for the applications.</p> Lay Summary <p>The review article summarizes the biomaterials used for the 3D bioprinting applications and their elaborated characterization processes. Different techniques like FTIR, rheological analysis, and mechanical analysis are described in detail.</p>