The functions and recognition mechanisms of membrane protein (MP) complexes are dictated by their binding affinities. Mutations in these complexes not only affect the binding affinity but also impair critical functions, potentially leading to diseases. However, due to their intricate structures, the binding affinity of MPs remains less explored compared to globular proteins. We describe Membrane Protein complex binding Affinity Database (MPAD, available at https://web.iitm.ac.in/bioinfo2/mpad/) , which is the first database dedicated to the binding affinity of MP complexes and their mutants along with sequence, structure, functional information, membrane-specific features, experimental conditions, and literature information. The current version of MPAD contains ~5400 experimental binding affinity data from 950 proteins. MPAD has an easy-to-use interface and options to build search queries, display, sort, download, and upload the data are among the other features available to users. We illustrate detailed protocols for data retrieval using different user-friendly search, display, and sorting options. Further, we also provide details on the contents of MPAD, data upload and download, cross-linking with other databases, and visualization options. Finally, we discuss potential applications of MPAD in membrane protein research.