Abstract. A formulated protein meal developed by Kogan (1990) for adult female Aedes aegypti mosquitoes was evaluated and modified to increase egg and pupal yield. A vigorous laboratory colony was maintained with the females fed exclusively on this dietary formula for about twenty-five generations over more than 2 years. Extra modifications were made to produce a diet suitable for Anopheles arabiensis and Anopheles stephensi females to produce eggs. Both formulations contain bovine albumin, haemoglobin and globulin in a ringer based solution, plus ATP as a phagostimulant for Ae.aegypti. Compared to Kogan's original, our Aedes formula doubled the production of pupae per female after a single meal, although the yield was still significantly lower than from mosquitoes fed on animal hosts or defibrinated pig blood. In varying the proportions of different constituents during attempts to optimize the formula, no relationship was found between total protein content (within the range 80–220 mg/ml) and fecundity, percentage hatch or pupal yield of Ae.aegypti. Equivocal results were found when an isoleucine supplement was added to the formula.