This article is an extensive review of the literature on the mechanical and thermal properties of glass-reinforced structural composites at cryogenic temperatures. The objective is to provide an understanding of the general magnitude of property values obtainable within the cryogenic temperature range, to provide a feel for the relative literature ranking of specific composite types with regard to a specific property, and to impart an understanding of the temperature sensitivity of the property of interest. A bibliography and bibliography-property cross-reference is included. This is Part I of a two-part series. Part II will consider advanced composites.