Amino terminus-blocked peptide boronate compounds of Formulas I and II are useful for inhibiting Fibroblast Activation Protein (FAP) and other proteases, and for treating disorders mediated by FAP. Methods of using the amino terminus blocked peptide boronate compounds, and stereoisomers, tautomers, solvates and pharmaceutically acceptable salts thereof, for in vitro, in situ, and in vivo diagnosis, prevention or treatment of such disorders in mammalian cells, or associated pathological conditions are disclosed.