A method has been developed for the deposition of uniform thin films of Parylene C by the use of laser monitoring. By monitoring the reflectivity of metal-coated substrates during growth of the polymer films, effective anti-reflecting coatings have been deposited which have appreciably improved some properties of chalcogenide and Gd-Co alloy films. The optimum conditions for Parylene C film deposition were found by studying the effect of dimer source temperature and system pressure on the deposition rate and film quality and uniformity. These results are reported and the apparatus is described. © 1975.