Although there is no consensus on the exact definition of precision medicine, it is generally agreed upon that the term entails diagnosis and therapy tailored to the individual patient. Precision medicine has seen major advances in the past two decades, many of which are relevant to ischemic stroke or transient ischemic attack (TIA). Advances include substantial improvements in high-throughput technologies, collaborations between the fields of biology and medicine, increasingly advanced biomedical informatics, the development of multimodal brain imaging techniques, as well as the widespread usage of electronic medical records and big data. Precision medicine in ischemic stroke or TIA is still in its infancy, but there have already been changes in clinical care from a one-size-fits-all model to a more precise, individualized approach. However, further studies are urgently needed to bridge the gaps between clinical studies and precision clinical practice. We discuss here the advances and challenges for precision medicine in ischemic stroke or TIA at its current stage, focusing on genetic predispositions, pharmacogenetics, omics, brain imaging and big data.