The conventional wisdom regarding the cultivation of cash crops (such as opium) is based on the assumption that raising a cash crop implies a certain degree of development of the productive forces of the economy. Having reached that degree, it is argued, the economy is better able to release portions of its land and labour from the production of basic necessities, i.e., food crops, and allocate them to the production of crops which are not immediately and directly consumed, but rather are produced to be exchanged in the market. This approach presupposes a relatively well-developed market economy and the existence of a relatively efficient transport system, both being, among other preconditions, essential for the emergence and development of an economy based on exchange. The main objective of this paper is to show that this model, despite being applicable to the Western European economies at an earlier stage of their industrialization, does not necessarily explain the situation in Iran during 1850–1906 (the period under review). We further argue that the production of opium or other cash crops had little to do with the development of Iranian agriculture or the development of the productive forces in the economy as a whole.