Disclosed are epoxy resins exhibiting a highly favorable combination of tensile strength and elongation with respect to prior art epoxy systems. The elastomeric epoxy resin systems of the invention are prepared utilizing a curing agent containing at least one monoprimary amine, and are particularly useful in applications such as, for example, castings, potting, composites, crack sealing, coatings, adhesives, roofing materials, flooring or reinforced membranes.