Abstract: A rubber-modified epoxy adhesive and the method of making the same is dissed for use in bonding graphite-epoxy composite structures. The adhesive comprises a two-part formulation, one part being a reaction product of a carboxyl terminated reactive liquid rubber prereacted with a bisphenol A epoxy resin so that linear epoxy-rubber chains are developed. The second part of the adhesive is an amine curing agent. One effective example of the adhesive is formulated as follows: approximately 4 parts by weight of the bisphenol A epoxy resin is mixed per part of a carboxyl terminated butadiene acrylonitrile rubber and heated to 170.degree. C. At 160.degree. C., a catalyst of approximately 0.01 parts by weight of triphenyl phosphene per part of the rubber is added and the mixture stirred for one hour at 170.degree.-175.degree. C. to provide the reaction product.