Under vacuum conditions, the accumulation of low fluence laser pulses generally leads to an organic contamination of the surface irradiated. This phenomenon reduces the optical component lifetime. Experimental conditions such as laser characteristics, environment composition and structure of the coating strongly influence the contamination mechanisms. Silica being the most employed material for optical coatings, this study aims at describing the laser-induced contamination influence of silica coatings deposition techniques. E-Beam evaporated and Ion Beam Sputtered silica thin films have been exposed to several billions 600 mJ/cm2 - 532 nm laser pulses under vacuum. This paper presents the observations made on laser-induced contamination and discusses the physical mechanisms involved.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.