Stable concentrated oil-in-water (O/W) emulsions were prepared and their application for heavy oil pipeline transportation was investigated using very viscous Malaysian heavy crude oil. Two Malaysian heavy crude oil samples, Tapis and a blend of Tapis and Masilla, were used to produce heavy crude oil-in-water emulsions. The diverse factors affecting the properties and stability of emulsions were investigated. There was a restricted limit of 68 vol. % and 72 vol. % for crude oil content in the emulsions, and beyond that limit, the emulsion underwent phase inversion. The study revealed that the stability of the oil-in-water emulsion stabilized by Triton X-100 increases as the surfactant concentration increases, with a subsequent decrease in the crude oil-water interfacial tension (IFT). Increasing the oil content, the speed and duration of mixing, the salt concentration and the pH of the aqueous phase of the emulsion; resulted in increased emulsion stability, while increases in the temperature of the homogenization process substantially reduced the viscosity of the prepared emulsions.