Neuronal activity causes substantial sodium transients in fine cellular processes such as dendrites and spines. The physiological consequences of such sodium transients are still largely unknown. High resolution sodium imaging is pivotal to study these questions. To date, two-photon imaging with the fluorescent sodium indicator SBFI (sodium-binding benzofuran isophthalate) has been the method of choice. Recently, CoroNa-Green (CoroNa), a new sodium indicator dye with an absorbance maximum at 492 nm has become available. We have compared the properties of SBFI with those of CoroNa by performing sodium measurements combined with whole-cell patch-clamp recordings in neurons of acute mouse hippocampal slices. Using non-confocal camera imaging, we show that CoroNa is suitable for measuring intracellular sodium transients evoked by application of the non-NMDA receptor agonist AMPA. However, considerable transmembrane dye leakage and lower sodium sensitivity are clear disadvantages when compared to SBFI. We also tested CoroNa for its suitability for high-resolution imaging of sodium transients using a confocal laser scanning system. We demonstrate that CoroNa, in contrast to SBFI, can be employed for confocal imaging using a conventional argon laser and report the first sodium measurements in dendrites using this dye. This work was supported by the DFG.