In 2011, 8960 suspected measles cases were investigated. There were 235 confirmed as measles (among them, 7 cases were confirmed by lab, 17 epi-link cases and 211 clinically confirmed cases) in the Northern region of Viet Nam. Dates of onset were from January to June 2011. Most of the cases were 10 - 14 years old (28.5 percent), 1 - 4 years old (25.5 percent) and 1 year old (10.6 percent). The measles cases were identified in 26 districts. A hot spot, cluster of districts with high number of measles cases were detected including Sop Cop, Song Ma, Thuan Chau, Mai Son, Son La districts. A small measles outbreak (23 cases) occurred in Huoi Duong village, lasted for 2 weeks with Basic reproductive number, Ro