Study of the functional response of the fourth instar larvae and adult rnaks and females of Diomus sp., (Coleoptera: Coccinellidae) was conducted usíng densities of 5, 10, 20, 30, 40 and 60 individuals of Aphis craccivora Koch (Homoptera: Aphididae). Fourth instar larvae of Diomus sp. consumed more prey than males and females in each prey density. When the prey density was five aphids, males consumed more individuals than females, but as the prey density increased, females consumed more prey than males. Prey consumption by different life stages of Diomus sp was proportional to the prey densities, whereas the percentage of prey consumption was inversely proportional to prey densities. These results indicate that different life stages of Diomus sp. exhibited a Holling Type II functional response.