This study assessed the effect of urban supplemental measles vaccination campaigns (1997–1999) in Mozambique that targeted children aged 9–59 months. Reported measles cases were analyzed to the end of 2001 to determine campaign impact. Hospital inpatient data were collected in the national capital and in three provincial capitals where epidemics occurred the year after the campaigns. Measles epidemics followed campaigns in the capital city, in 4 of 9 provincial capitals, and in 39 of 126 districts. Reasons for limited campaign impact included a low proportion of urban dwellers, the geographic location of some provincial capitals, the limited target age group, and low routine and campaign coverage. Routine immunization and disease surveillance should be strengthened and campaigns must achieve >90% coverage and target wider age groups and geographic areas in order to reach a high proportion of persons susceptible to measles.