This article develops an integrated perspective to study whether formalization can significantly reduce precariousness for informal workers. This perspective combines the analysis of employment dualism with that of rural–urban dualism and the analysis of the production sphere with that of the social reproduction sphere. By applying this integrated framework to the case of a state-owned enterprise (SOE) in China, this article finds that formalization does little to reduce precariousness for the migrant agency workers there. Migrant agency workers in China are in a precarious position not only because of their employment status but also because of their incomplete citizenship and the commodification of social reproduction materials. With the compensation gap between formal and agency workers narrowed primarily owing to the deterioration of formal employment, formalization has little effect on increasing the income of agency workers or alleviating the financial pressure upon them in the sphere of social reproduction; neither can formalization raise migrants up to full citizenship or reduce related precariousness.