A Li+/Na+ exchange reaction was performed at 140 degrees C under hydrothermal conditions to react alpha-NaFeO2 (also prepared hydrothermally) with a large excess of LiOH . H2O, either in methanol or in ethanol, used as solvents. Each of the XRD peaks obtained from the hydrothermally ion-exchanged sample are indexable using the rhombohedral (hexagonal) unit cell of layered-LiFeO2. The chemical composition of the sample is estimated to be Li0.8Na0.2FeO2. The magnetic properties of Li0.8Na0.2FeO2 are quite similar with layered-LiFeO2, rather than those of alpha-LiFeO2.