OBJECTIVE An epidemiological study on measles was conducted among the under five children in slum areas of Kolkata to assess the incidence of measles. METHODS 20 cluster sampling technique was followed and in each cluster 250 under five children were covered. Paramedical workers identified children of the target of age group who had history of measles in past one year and the medical officer confirmed the diagnosis following standard case definition. RESULTS Incidence of measles was found as 5.76%. Incidence was equal in both the sex groups, but found more among infants. The incidence of measles gradually declined with the increase of age strengthening the view in favor of early immunization. Amongst the measles cases only 19.7% were immunized with measles vaccine. 100% of measles cases gave history of rash, 98.9% had history of fever, 82.8% reported that the rash started from face and progressed downwards to abdomen and leg. Cough, redness of eye and discoloration of skin were reported by 97.5%, 83.8% and 65.2% measles cases respectively. Only 16.9% and 8.6% children received Vitamin A oil before and after the illness respectively. 49% gave history of exposure to measles cases and 46.6% cases had measles within 2 weeks incubation period. CONCLUSIONS The study highlighted the necessity of timely measles vaccine coverage, additional dose at a higher age and Vitamin A supplementation through IEC activities.