Entorhinal cortex (EC) transfers multimodal information to hippocampus CA1 neurons via indirect and direct pathways. By using ChR2-assisted circuit mapping method, in vivo optogenetics and electrophysiology, we show that excitatory projections from lateral entorhinal cortex selectively target a subpopulation of morphologically complex, calbindin-expressing pyramidal cells (cPCs) in CA1, forming a distinct direct circuit that is required for olfactory associative learning. The cPCs develop more selective spiking responses to odor cues during learning, and may function as key players integrating spatial and non-spatial information in the hippocampu.