Rhythmically bursting neurons are fundamental to neuronal network function but typically are not considered in the context of primary sensory signaling. We now report intrinsically bursting lobster primary olfactory receptor neurons that respond to odors with a phase-dependent burst of action potentials. Rhythmic odor input as might be generated by sniffing entrains the intrinsic bursting rhythm in a concentration-dependent manner and presumably synchronizes the ensemble of bursting cells. We suggest such intrinsically bursting olfactory receptor cells provide a novel way for encoding odor information.