ABSTRACTWe describe a community-wide outbreak of measles due to a D4 genotype virus that took place in the Region of Madrid, Spain, between February 2011 and August 2012, along with the control measures adopted. The following variables were collected: date of birth, sex, symptoms, complications, hospital admission, laboratory test results, link with another cases, home address, places of work or study, travel during the incubation period, ethnic group, and Mumps-Measles-Rubella (MMR) vaccination status. Incidences were calculated by 100,000 inhabitants. A total of 789 cases were identified. Of all cases, 36.0% belonged to Roma community, among which 68.7% were 16 months to 19 y old. Non-Roma cases were predominantly patients from 6 to 15 months (28.1%) and 20 to 39 y (52.3%). Most cases were unvaccinated. We found out that 3.0% of cases were healthcare workers. The first vaccination dose was brought forward to 12 months, active recruitment of unvaccinated children from 12 months to 4 y of age was performed and the vaccination of healthcare workers and of members of the Roma community was reinforced. High vaccination coverage must be reached with 2 doses of MMR vaccine, aimed at specific groups, such as young adults, Roma population and healthcare workers.