A sterile holidic diet was formulated that has sustained 18 generations of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), an aphid generally restricted to legumes. Although apparently satisfactory for continuous propagation, the diet did not promote optimum growth and reproduction. Pea aphids reared on the diet showed a mean adult weight of 1.6 mg, 68% of that of plant-reared aphids. The mean number of progeny per diet-reared aphid per day was 0.54, compared to a mean of 6 per day among plantreared aphids. The mean generation period was 13.1 days for the first 10 generations on the holidic diet. A feeding apparatus was developed that allowed the aphids to feed undisturbed for a week, yet permitted the diet to be changed more frequently. The feeding apparatus consisted of a refillable diet chamber with a Parafilm® membrane above an aphid chamber. The aphids were placed directly on the membrane of the diet chamber when they were transferred from one feeding apparatus to another, eliminating the need for them to climb up to the membrane. As many as 200 adults were reared in a single cage, and adult populations of 600–1000 were maintained.