Thin films of lanthanum monosulfide (LaS) have been successfully deposited on Si substrates by pulsed laser deposition. The values of deposition parameters (chamber pressure, substrate temperature, substrate-to-target separation, laser energy, repetition rate, and spot size on the target) leading to a successful growth of films in their cubic rocksalt structure are identified. The films are golden yellow in appearance with a mirror-like surface morphology and possess a sheet resistance around 0.1 Omega/square. X-ray diffraction analysis of thick films (several microns) leads to a lattice constant of 5.863(7) Angstrom, which is close to the bulk LaS value. High-resolution transmission electron microscopy reveals the films to be comprised of nanocrystalline regions separated by amorphous ones. The root-mean-square variation of film surface roughness measured over a 1 mum x 1 mum area is found to be 1.74 nm by atomic force microscopy. These films have potential for semiconductor, vacuum microelectronics, and optoelectronics applications. (C) 2005 American Vacuum Society.