Styrene-butadiene (S/B) latex modified concrete overlays are being used to protect new bridge decks from rapid deicer-borne chloride intrusion and also in bridge deck rehabilitation efforts. The purposes of this research were to evaluate several commercially-available S/B latex modifiers for bridge deck overlay concrete; and to develop chemical specifications for the material, a prequalification program to permit evaluation of other S/B latex modifiers which become available, and a certification program to insure the user receives a prequalified product. The chemical and physical properties of the latex emulsions were studied (percent solids, percent butadiene, particle size, surface tension, viscosity, etc.) and the material from each manufacturer was finger printed using infrared spectroscopy. The physical properties of concrete made with each material were also determined (workability, strength-compressive, flexural and bond, freeze-thaw and scaling resistance, and chloride permeability).