TMFunction is a database of functional residues in alpha-helical and beta-barrel membrane proteins. Each protein is identified with its name and source alongwith the UniProt code. The protein data bank (PDB) codes are also given for available proteins. Different methods and experimental parameters, for example, affinity, dissociation constant, IC50, activity etc. are given in the database. Further, we have provided the numerical experimental value for each residue (or mutant) in a protein. The experimental data are collected from the literature both by searching the journals as well as with the keyword search at PubMed. In addition, complete reference is given with journal citation and PMID number.