To provide a glass-fiber cord for rubber reinforcement to be embedded for reinforcing a rubber product such as transmission belt, making no coating workplace poor when a number of glass fibers is coated with a sizing agent, and suitable for preventing the glass-fiber filaments from fraying and coming into sight from the end surfaces of the transmission belt after embedded in a matrix rubber.

The glass-fiber cord for rubber reinforcement is such as to be obtained by laying 2-3 strands made by convergence through bundling 200-800 glass-fiber filaments having a diameter of 5.0-7.0 m, and being sized with a sizing agent including an aminosilane and an epoxy resin. The twist count in the longitudinal direction of the strand is 3-4 turns/25 mm.