Abstract: Laboratory experiments were conducted to measure the functional and numerical responses of Eretmocerus mundus Mercet parasitizing cotton whitefly, Bemisia tabaci Gennadius. Parasitoids were isolated singly for 24 h in 5 cm petri dishes with either 5, 10, 20, 40, 60 or 100 second nymphal stages of B. tabaci. Results showed a typical type II functional response, with up to 43.2 hosts attacked when 100 hosts were provided. The rate of attack and handling time were 0.0465 and 0.3341 days, respectively. At above mentioned densities, the parasitoids lived an average of ≈4 days. At host densities of ≤20 host/day, the total number of eggs laid was limited by the number of hosts available. Total fecundity was highest with an average of 196 eggs/female at density 100.