Stem cells provide a promising therapy for treating stroke. Several imaging techniques provide the possibility of the visual representation of biological processes of transplanted stem cells in vivo. Further means of monitoring the transplanted cells safely, noninvasively, and longitudinally would contribute to the understanding of the underlying stem cell therapeutic mechanism. In this chapter, we describe the state-of-the-art methods of monitoring transplanted stem cells in vivo, including magnetic resonance imaging (MRI), radionuclide imaging, and optical imaging. Their principles vary and each has advantages and drawbacks. Presently, no single technique is excellent through ideal criteria; the combination of multiple imaging modalities is thus an attractive strategy. © Springer Nature Singapore Pte Ltd. 2017.