This study investigates the transformation behavior of highly Ni-rich 60NiTi alloys after aging at 600 degrees C for 3 h. After 600 degrees C-3h aging, R-phase disappeared and alloy transformed in one step. The latent heats of austenite to martensite and martensite to austenite transformations were 13 Jg(-1) and 16.4 Jg(-1), respectively, for 600 degrees C-3h aged alloy. The elastic strain energy of 0.75 Jg(-1) was obtained in aged alloy. The maximum recoverable transformation strain of 1.7% is obtained under 500 MPa in compression. The superelastic behavior was observed accompanied with a recoverable strain of 1.4%, even high stress level of 1000 MPa is applied.