The effect of the parasitoid/host (P/H) ratio on superparasitism of Ceratitis capitata (Wiedemann) mature larvae by Psyttalia concolor (Szepligeti) was evaluated in laboratory mass-rearing conditions. Three P/H ratios were tested: 1/2, 1/1 and 1/0.5. The experimental conditions were managed in order to enhance the superparasitism phenomenon. Only the ratio P/H 1/2 produced parasitoid emergence, with a value of 15.33%. This was markedly lower than the P. con-color emergence percentage usually obtained in standard mass-rearing conditions. A very high rate of superparasitism was found in the dissected host larvae sample, with a mean egg number considerably exceeding the optimal value of two. At the ratios 1/1 and 2/1 a total parasitization of the host was obtained, but with the complete annihilation of parasitoid progeny. More efficient mass-rearing results will be obtained if appreciably lower parasitoid/host ratios are maintained. Under such conditions, optimal time allocation and host selection could allow the parasitoids to produce the best host acceptance and to maximize their own fitness. Techniques; Care in captivity; Life cycle and development; Development; Metamorphosis; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Ceratitis capitata (Tephritidae); Hymenopteran parasites; Psyttalia concolor; Parasitoid/host ratio effects on parasitoid emergence rate, mass rearing Psyttalia concolor (Braconidae); Rearing techniques; Emergence; Dipteran hosts; Ceratitis capitata; Parasitoid/host ratio effects on parasitoid emergence rate, mass rearing none