Since the 1950s, the rapid growth of Istanbul has stimulated a wide range of retail activities. Notable among those are the periodic markets, a basic type of informal exchange mechanism supported by continuous rural migration into Istanbul. The availability of fresh produce and inexpensive goods combined with the locational convenience and enjoyable atmosphere make periodic markets widely attractive, and their number and size rapidly increased between 1980 and 2002. The paper investigates the relationship between the number and size of periodic markets in various districts of Istanbul to their population, income and distance to CBD using regression. The results show a positive correlation between the number of periodic markets and the number of traders serving the periodic markets and the population of the districts, and the number of markets increased toward the periphery following population growth. Retailers, customers, shopkeepers and residents in the surrounding areas of the periodic markets were surveyed - there are complaints about pollution, traffic congestion, noise and lack of parking place on market days. (c) 2005 Elsevier Ltd. All rights reserved.