A cross-sectional, community-based study was conducted in 32 slums of Udaipur city to assess the prevalence of missed opportunities for measles immunization, reason for their occurrence and potential impact of avoiding them on measles immunization coverage. Two hundred and sixty-five children, between the age of 9 and 24 months were enlisted for the study, using a practical cluster sampling method. Immunization status of the children, visits to health facilities after 9 months of age and reasons for non-immunization were noted. Missed opportunities for measles immunization was defined as any visit by an eligible child to a health facility, which did not result in his/her vaccination. Measles immunization coverage amongst the study population was 50.61%. The prevalence of missed opportunities for measles immunization was 14.3%. Not offering measles immunization at curative visits (86.9%) was the major reason for missing opportunities. Avoiding all missed opportunities could have increased the measles immunization coverage to 64.9%.