We report a low-temperature liquid-phase synthesis method of small AgI quantum dots with a diameter of 3.0 nm. The synthesized AgI quantum dots were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction measurements. In the UV-visible spectrum, the AgI quantum dots had a large blue shift in the absorption band compared to bulk one because of the quantum size effect.