Major outbreaks with large attack rates resulting in as high as 15-20% case fatality rates have been reported in Ethiopia. There is a paucity of information on measles outbreak response activities and surveillance system performance in Eats Wollega Zone in general and NunuKumba district in particular, Ethiopia. A descriptive cross-sectional survey was employed. The data was collected using semi-structured questionnaires, and a secondary data was taken from the line list of cases. Purposive sampling technique was used. Quantitative data was analyzed using Microsoft Excel 2010 while the qualitative data was themed; analyzed and then triangulated with quantitative result. The result was displayed by graphs, tables and Epi-curve. The overall Attack rate and Case Fatality Rate were 1.05% and 0.41% respectively. The most affected age group was under five year’s children 552(56.55%). The outbreak reached climax at middle of January and declined by the middle of February, 2020. Age group of 1-4years had higher attack rate. Poor health seeking behaviour, poor surveillance system, lack of operational surveillance guidelines and protocols, and dalliances of lab specimen result written feedback written recommended time period were the probable factors for the outbreak. Therefore, training of human power, and surveillance system should get due attention. f
Keywords: Evaluation, Measles outbreak, NunuKumba, District, Surveillance performance, East Wollega Zone.