Phlebotomine sandflies, like many other hematophagous Diptera, require a source of carbohydrate for sustenance. This paper is an attempt to establish useful criteria for sugar feeding of these flies. Utilizing the Panamanian Lutzomyia Trapidoi (Fairchild & Hertig), a number of parameters associated with experimental feeding were investigated. Of 11 sugars tested, 5 were preferred: sucrose, fructose, maltose, raffinose and glucose. These 5 sugars are primary constituents of nectar, probably the most important energy source in nature for hematophagous flies. Honey was less acceptable than fructose or corn syrup (Karo). Rate of sugar acceptance was unaffected by concentration, pH, NaCI content, color of the solution or temperature. Concentration of sugar solution had no appreciable effect on fly longevity. Higher feeding rates were obtained utilizing a new holding vessel (styrofoam cup).