Anomalies in the heat capacity curves of AgI have been detected near the temperature of 150 K. Powder X-ray diffraction experiments have been performed in the temperature range 23-299 K. These anomalies were observed for the specimens which experienced the alpha- to beta/gamma-phase transition (heated up to 773 K and then quenched to room temperature) but became unobservable in the subsequent heating cycles. The various values (1.5, 13.0 and 4.1 Jmol(-1)) of the enthalpy of transition obtained depend on the thermal history. It can be considered that the anomaly is a transformation from the intermediate (high-pressure) phase to the beta/gamma phase.