In Karl Marx's critique of political economy, commodity fetishism is the perception of certain relationships (especially production and exchange) not as relationships among people, but as social relationships among things (the money and commodities exchanged in market trade). As a form of reification, commodity fetishism perceives economic value as something that arises from and resides within the commodity goods themselves, and not from the series of interpersonal relations that produce the commodity and evolve its value.
The theory of commodity fetishism is presented in the first chapter of Das Kapital (English: Capital. Critique of Political Economy) (1867), at the conclusion of the analysis of the value-form of commodities, to explain that the social organization of labor is mediated through market exchange, the buying and the selling of commodities (goods and services). Hence, in a capitalist society, social relations between people—who makes what, who works for whom, the production-time for a commodity, et cetera—are perceived as social relations among objects; depending on the social function of the exchange, objects acquire a certain form (for example, if the function is to render possible exchange, the object acquires value; if its function is one of hiring a worker, then the object becomes capital). On the market, the commodities of each individual producer appear in a depersonalized form as separate exemplars of a given type of commodity regardless of who produced them, or where, or in which specific conditions, thus obscuring the social relations of production.
Marx explained the sociological concept underlying commodity fetishism thus:
As against this, the commodity-form, and the value-relation of the products of labour within which it appears, have absolutely no connection with the physical nature of the commodity and the material relations arising out of this. It is nothing but the definite social relation between men themselves which assumes here, for them, the fantastic form of a relation between things. In order, therefore, to find an analogy we must take flight into the misty realm of religion. There the products of the human brain appear as autonomous figures endowed with a life of their own, which enter into relations both with each other and with the human race. So it is in the world of commodities with the products of men's hands. I call this the fetishism which attaches itself to the products of labour as soon as they are produced as commodities, and is therefore inseparable from the production of commodities.