An ideal dental repair material should possess certain exclusive properties such as adequate adhesive ability, dimensional stability, biocompatibility, bioactivity etc. Calcium silicate based materials seem to have intrinsic properties suitable for their clinical use, such as good sealing correlated to expansion, and the ability to set in the presence of fluids, bioactivity, the release of ions acting as epigenetic signals, and good biological properties. The introduction of MTA was considered as a major break-through in the history of material science. Biodentine has been recently introduced as the “the first all-in-one, bioactive and biocompatible material for damaged dentin replacement”. This article attempts to compare the properties and clinical applications of MTA and Biodentine.