Precise and reliable presentation of odorants to animals is crucial for olfactory studies. Although odor stimulation systems in anesthetized or awake, head‐fixed animals are well established, temporally precise odor presentation in awake, freely moving animals remains a challenge. Here, we describe a new odor stimulation system which presents odors directly to the nostrils of freely moving mice. The system comprises 3 modules: an odor‐delivery module, an odor‐generation module, and a control module. The new system is precise and temporally reliable, and odor stimulation can be triggered by specific sniffing phases or other events. Moreover, the system can be combined with neural recordings, such as electrophysiology, and olfactory behavioral tests to investigate how neurons in the brain represent odor information during individual olfactory behaviors. This innovative odor stimulation system may replace traditional stimulation systems: It will enable precise odor presentation in a wide range of olfactory studies in freely moving animals.