The specific heat under constant pressure, C-p, of intermetallic compounds Hf2Fe, Hf2Co and Hf2Rh with the Ti2Ni structure was obtained by means of differential thermal analysis in the temperature range 275-740 K. The results differ significantly from the Debye theory, even when a correction for optical phonons in Einstein approximation is considered, which indicates existence of a defect contribution to the specific heat. Relative entropy has been determined and the obtained results were fitted and analysed. The anomalous temperature behaviour of C, is discussed, having in mind results of previous investigations of these and similar systems, obtained by other methods.