This paper is an exposition of Karl Heinrich Marx’s Theory of Labor and the Working Conditions of Blue-Collar Workers. Through his Theory of Labor, Marx demonstrated that the existence of capitalist makes limit a human person’s liberty. Moreover, the problematic working conditions of bluecollar workers can be solved, according to Marx, by overcoming the socioeconomic system of capitalism and replacing it with communal ownership through socialism. It is the researchers’ analysis in this paper that the ideal labor of Karl Heinrich Marx can be found in his work. For Marx, the basis of human society is labor. Labor means the submission of human person into his work for means of his survival and for the actualization of his being. In addition, human person does not only change the matter in nature, but he simultaneously changes his nature. Thus, the Theory of Labor of Karl Heinrich Marx speaks about the importance and value of both worker and as being human; for his theory is basically a philosophy of human person. Eventually, the rationale in conducting this study was to expose Karl Heinrich Marx’s Theory of Labor because there is a need to understand the true meaning of human work and the importance of labor in our society. As he submits in the system of labor, he experiences some conditions in working where every worker must be entitled for a just and dignified working conditions.