Sintering of amorphous calcium phosphate (ACP) is challenging because of its metastable structure. This structure is irreversibly altered when ACP is heated to temperatures above a few hundred degrees Celsius that leads to crystallization and transformation of ACP to other less bioactive phases. Therefore, only sintering techniques that enhances mass transfer at very low temperatures can potentially be used for ACP densification . In this study, for densification of ACP, we used the so-called cold sintering process (CSP) . We investigated the effect of CSP parameters such as sintering temperature and presence or absence of transient liquid (water) on densification and structure of ACP.