Data on the operational efficacy of DDT indoor residual spraying against Phlebotomus argentipes, the vector of kala-azar in India, are scarce. We therefore undertook a study of the impact on kala-azar and its vector of DDT indoor residual spraying in the Varanasi district of eastern Uttar Pradesh. Preliminary results indicate that after two rounds of DDT spraying in one village no P. argentipes were found during the peak vector season; in contrast, a large number of these sandfies were collected in the unsprayed comparison village.