Proteomics has emerged as a powerful tool in clinical biomarker research. In the field of transplantation, proteomics aims not only at developing noninvasive tools for immune monitoring and identifying biomarkers of allograft rejection but also to gain mechanistic insights into the pathophysiology of an alloimmune response and hence defining new therapeutic targets. A basic knowledge of proteomic technology is a prerequisite to appreciate the complex data generated and required for critical evaluation/interpretation of proteomic-driven studies. This review provides an overview of proteomic approaches and its underlying concepts and discusses the advantages, clinical implications, challenges, and limitations of this exciting modality in transplantation.