A method that can determine uniquely the elastoplastic properties from indentation loading and unloading curves has been developed. It is based on finite element modeling and inverse analysis of two separate indenters. The approach was validated by numerical experiments using a fictitious material. It was demonstrated that the proposed method can uniquely recover the elastoplastic properties using only indentation load-displacement curves of two indenters. Although the proposed procedure has been used to predict elastoplastic strain hardening behavior, it is also applicable to estimate other mechanical properties where there are more than two unknown parameters, such as rate-dependent behavior.