A main characteristic of the working class has been its peasant origins. The rapid growth of the working class in the 1960s and 1970s was the result of migration from villages to cities. There also has been some migration from small towns to larger cities and from economically depressed areas, such as Baluchestan and Kordestan, to more economically vital regions. The result of these population transfers has been an inability of urban services to keep pace with the population growth and the consequent spread of slum areas. In 1987 south Tehran was still Iran's most extensive urban slum, but other large cities also had notable slum sections. It was in these areas that marginally employed and unskilled workers were concentrated. Immediately after the Revolution, the government announced its intention of making living and working conditions in rural areas more attractive as a means of stemming rural- to-urban migration. Although the slowdown in the economy since the Revolution may have contributed to a generally reduced rate of urban growth, there was no evidence that migration from the villages had ceased. The preliminary results from the 1986 census indicated that such cities as Mashhad and Shiraz have grown at even faster rates than before the Revolution.

Data as of December 1987