The term sprawl has entered into urban planning literature since the middle of 20th century and nowadays it’s one of the main subjects of concern in many countries. Although the research on sprawl originated in the studies of the American cities, but it has been used in many different countries with various natures, indexes and results. The trend of expansion of cities and metropolitan areas has many positive and negative results and it depends on different geographic, economic, social and political characteristics of cities and metropolitan areas. Although our cities had experienced slow expansion long ago, but the concept of sprawl has entered into our planning literature now. Zanjan is one of the cities in our country that have had a rapid expansion in recent years and vast areas of the city have been built up recently. Findings show that the initial expansion of the city has been due to its physical position and its natural population growth, but over the time, the expansion of the city has been affected by various factors such as economy, urban development plans, policies and different groups that have brought about the sprawl phenomenon to the this city. In order to examine the sprawl phenomenon in Zanjan, based on Ewings findings his study of the American Metropolitan Areas, we chose ten variables that could depict the sprawl phenomenon in Zanjan city setting. Factor analysis was applied to these selected 10 variables to find the underlying dimensions of sprawl in the Zanjan city. Four factors were extracted, namely: density, mixture of land uses, centeredness and accessibility. The results of the factor analysis were transformed into maps using GIS software. The findings indicate that areas in the central parts of the city have the least rating of sprawl and it gets aggravated by moving away from the center, so that the most sprawls is seen in eastern, northeastern and western parts of the city. In addition, comparing sprawl and expansion process of the city in different years show that the central zones that had formed in the initial period, have low level of sprawl and the zones that have been built in recent years, tend to have sprawled most. It was seen that in recent years many causes have led to the sprawl in Zanjan City. Initial growth of the city was because of the geographic location of the city and the communication network that Zanjan is part of it and the icural growth of population. This growth obeyed natural and climatic characteristics, but over the time, the growth of the city was affected by some other factors such as economic affairs, policies, plans and various groups. Findings of this research support Ewing`s viewpoints and show that by considering sprawl characteristics and surveying the extracted factors and taking into consideration the elements that affect sprawl, we can control of the city growth in the future in similar instances by using appropriated policies.