We have prepared AgInS2 thin films by the spray pyrolysis technique. The effects of the growth temperature and the chemical composition of the solution on the structural, optical and electrical properties of the films have been studied. It was found that growth temperatures above 400 degreesC lead to single-phase chalcopyrite type AgInS2 films, but deposition temperatures lower than 400 degreesC lead to mixed chalcopyrite and orthorombic structure films. All the films grown here show n-type conductivity, with room temperature resistivity in the range between 10(3) and 10(5) Omega cm. The absorbance derivative spectra of single-phase AgInS2 films revealed two optical energy gaps at approximately 1.87 and 2.03 eV, attributed to the fundamental edge and to the valence band splitting by the crystal field, respectively.