Because of a low birth control rate among Hmong married couples, population growth of the ethnic group was much higher than the national rate. This investigation aimed to analyze birth control situations of and also to develop a practical guideline in providing birth control services to the ethnic group. The population involved in this participatory action research study consisted of 71 Hmong couples at Huay Nam Jang Village in Tambon Bo Kaew, Samoeng district, Chiang Mai province, from March to July 1973. It was found that Hmong women got married and became pregnant under the age of 20. They started birth control when they were 22 years with four children on average. They preferred sons to daughters and viewed that birth control was the responsibility of women. The study findings indicated that, for efficient birth control service provision, concerned agencies had to provide the services in accordance with socio-cultural contexts and the needs of service users.