The electrophysiological properties of 46 bursting cells and 39 regular firing cells were studied in the subiculum of rat combined hippocampal-entorhinal cortex slices. In bursting cells we found a significantly higher resting membrane potential than in regular firing cells. Upon hyperpolarization both cell types expressed a delayed inward rectification with a subsequent afterdepolarization. While in regular firing cells longer lasting depolarizing current injection caused a train of action potentials with a rather marked decline of discharge frequency, bursting cells displayed only little frequency accommodation. Regular firing cells usually displayed a fast and a slow afterhyperpolarization following a train of action potentials, while bursting neurons present only a slow afterhyperpolarization.