Nanoindentation has recently emerged as a powerful tool for measuring nano- and microscale mechanical properties in tissues and other biomaterials. This technique has been used to measure the mechanical properties of microstructural features in bone and teeth, investigate variations in mechanical properties with changes in tissue organization or composition in mineralized and soft tissues, and map mechanical properties spatially in complex biomaterials. Continuing advancements in indentation data analysis will increase the method's utility in the characterization of biomaterials.