Low measles vaccination coverage (VC) leads to recurrent epidemics in many African countries. We describe VC before and after late reinforcement of vaccination activities during a measles epidemic in Niamey, Niger (2003-2004) assessed by Lot Quality Assurance Sampling (LQAS). Neighborhoods of Niamey were grouped into 46 lots based on geographic proximity and population homogeneity. Before reinforcement activities, 96% of lots had a VC below 70%. After reinforcement, this proportion fell to 78%. During the intervention 50% of children who had no previous record of measles vaccination received their first dose (vaccination card or parental recall). Our results highlight the benefits and limitations of vaccine reinforcement activities performed late in the epidemic.