This essay presents a methodological analysis of one Marxian approach to development, the so-called modes of production (MOP) school. The three basic positions encompassed by the MOP school are examined in terms of the specific issues of the constitution of theories, the process of concept formation, and the status of concepts within theory in general. The MOP school is criticized for two major problems associated with its use of the concept of mode of production: the problem of economic determinism and the use of a strict theory-fact dichotomy.