This article examines the Vietnamese writings on overpopulation, racial decline and birth control that were published in Vietnamese journals in the 1930s. Navigating between different demographic and sexual discourses, both local and global, Vietnamese birth control activists took a stern and critical look at the compounding problems of overpopulation and racial decline in colonial Tonkin. They identified the Confucian pro-natalist traditions with its laissez-faire approach towards reproduction and childrearing as the roots of the overpopulation crisis in Tonkin. Rejecting the French solution of demographic balancing while stressing the linkages between reproduction and national standing, Vietnamese birth control activists called for cultural changes in the customs of marriage and family building, and a stricter surveillance over procreative and sexual behaviors. In the context of French surveillance and censorship, the Vietnamese debate on overpopulation and birth limitation provided rich fodder for local intellectuals to envision and articulate their aspirations for national revival and racial preservation.