The melon aphid , Aphis gossypii Glover (Hemiptera: Aphididae) , is one of the most important greenhouse and crop pests with a wide range of hosts, which causes damage to vegetable both in fields and greenhouses through feeding on vegetable sap and transmitting viral diseases. Green lacewing is one of the most important natural enemies of aphids and other pests of homoptera order in crop fields, orchards and greenhouses. In this study, functional response of third instar larvae of green lacewing feeding on 4 th instar nymphs of Aphis gossypii, was evaluated under laboratory conditions (25 ± 2 °C, 65 ± 5 % R H and a 16 L : 8 D photoperiod). Experiments was done inside Petri dish (diameter: 12 cm, height: 1 cm) on a leaf piece of cucumber as host plant for 24 hours. The functional response experiment were carried out with seven prey densities of 2 , 4 , 8 , 16 , 32 , 64 and 100 of 4th instar nymphs of Aphis gossypii in eight repetitions. Data were analyzed with SAS statistical software. Logistic regression was used to determine type of functional response and nonlinear regression to estimate parameters of searching efficiency ( a ) and handling time ( Th ). The result showed that the functional response was type II. Searching efficiency and handling time of Chrysoperla carnea on Aphis gossypii nymphs were 0.0745 ± 0.0164 and 0.3165 ± 0.0567, respectively. The data indicated that the Chrysoperla carnea may be a useful candidate for the biological control of Aphis gossypii.