The mossy fiber pathway has long been considered to provide the major source of excitatory input to pyramidal cells of hippocampal area CA3. In this review we describe anatomical and physiological properties of this pathway that challenge this view. We argue that the mossy fiber pathway does not provide the main input to CA3 pyramidal cells, and that the short-term plasticity and amplitude variance of mossy fiber synapses may be more important features than their long-term plasticity or absolute input strength.