Eretmocerus eremicus is the most abundant parasitoid of the Bemisia complex in North America. It can parasitize equally successfully the most common whiteflies in greenhouses, Trialeurodes vaporariorum and the Bemisia complex. The parasitoid is used in Europe for whitefly control, either alone or in combination with releases of Encarsia formosa. Life-cycle and demographic parameters of this parasitoid were evaluated using T. vaporariorum as a host. Fecundity, developmental time, juvenile mortality, sex ratio and longevity were determined under laboratory conditions (25 ± 1°C, 50-60% RH, 12:12 (L:D) h photoperiod) to be able to calculate the intrinsic rate of natural increase of the parasitoid on tomato plants, cultivars Moneymaker and Hayslip. The life-cycle parameters of the parasitoid did not differ significantly on the two tomato cultivars. The mean fecundity of E. eremicus was 162 ± 20 (mean ± s.e.) eggs on Moneymaker and 167 ± 20 eggs on Hayslip tomato cultivar. The developmental time was 22 ± 0.04 days, the juvenile mortality was 7% and the sex ratio was close to 1:1. Adult longevity was 14 ± 1.35 days. Life-cycle parameters indicate that the net reproduction (R0) was 91 and 86, the mean generation time (Tc) was 28 and 27, and the intrinsic rate of natural increase (rm) was 0.161 and 0.165 on the cultivars Moneymaker and Hayslip, respectively. The rm ranges among the rm's registered for other parasitoids used to control Bemisia sp. and Trialeurodes sp. Thus, E. eremicus seems a good candidate for biological control of two of the most important whitefly pests in greenhouses.