Studies on effective community-based intervention in areas inhabited by multiple ethnic groups are limited. The present study was performed to evaluate the impact of workshop activities in multiple local dialects guided by lay facilitators on vaccination coverage, sanitary living and health status in a northern district of Lao PDR. In target villages, facilitators were selected and trained to assist at village meetings to discuss health issues and develop and implement action plans. Manuals and posters with graphics were distributed. Skills were taught through demonstrations by specialists. The vaccination coverage among children and women improved significantly after 1 year. Villagers started using toilets, collecting and burning garbage, and isolating animals from human dwellings, and these activities were continued in 76, 84 and 87% of villages, respectively, 5 years after the start of the activities. The frequency of villagers falling ill was reduced in 67% of the villages. After adjustment for sociocultural characteristics and ethnicity, both the continuous sanitary living index and the reduction in the frequency of villagers falling ill were associated with the higher levels of community participation in the workshop activities. The results demonstrated that the community-based workshop activities improved vaccination coverage, sanitary living and health status. Participatory group discussions in local dialects and village activities led by lay facilitators, supervision and consultation by district trainers who were well recognized by villagers, and the distribution of pictorial educational materials can be an effective and sustainable health promotion approaches among multiethnic groups in under-resourced areas.