This publication presents the proceedings of ICPMSE-3, the third international conference on Protection of Materials and Structures from the Low Earth Orbit Space Environment, held in Toronto April 25-26, 1996. The conference was hosted and organized by Integrity Testing Laboratory Inc, (ITL), and held at the University of Toronto's Institute for Aerospace Studies (UTIAS), where ITL is located. Twenty industrial companies, seven wliversities and eight government agencies from Canada, USA, United Kingdom, France, Israel, Russia, Ukraine and the Netherlands were represented by over 55 participants indicating increasing international co-operation in this critical arena of protection of materials in space. Twenty-five speakers, world experts in their fields, delivered talks on a wide variety of topics on various aspects of material protection in space, Representatives from the Canadian, American, European and Israeli space agencies as well as from leading space research laboratories of major aerospace industries gathered at UTIAS to discuss the latest developments in the field of material and structure protection from the harsh space environment, These proceedings are organized into four sections: a) AONOV and Radiation Effects on Materials and Structures in the Leo Space Environment; b) Interaction of Matter with the LEO Environment; c) Large Scale Coating Process Developments for Protection in LEO; d) Synthesis and Modification of Materials and Surfaces for Protection in LEO, This is the third in our on-going series of bi-annual international space materials conferences wllich began in 1992 in Toronto. Jacob Kleiman, Integrity Testing Laboratory Inc.