The growth condition of the complex crystal KIO3·LiIO3 and its infrared spectra have been investigated. The morphology of the crystal has been determined. Its class is 2/m. The parameters of its cell are a = 11.189, b = 11.038, c = 8.262, β = 111°27′. The position of the optical indicatoid for the crystal, the refraction indices in the range of visible light and their Sellmeier's equations have been given.