Arsenic trisulfide (As2S3) thin films were deposited by a relatively new and simple successive ionic layer adsorption and reaction (SILAR) method using As2O3 and Na2S2O3 as arsenic and sulfide ion sources, respectively. The films were deposited on:glass and silicon(lll) wafer substrates. The concentration, pH, and temperature of anionic and cationic precursor solutions, immersion and rinsing times, and number of immersions have been optimized for obtaining good-quality As2S3 thin films. X-ray diffraction, optical absorption, and electrical resistivity techniques were used for characterization of the As2S3 thin films.