Urban transportation is one of the most important issues in urban planning and urban design. A transportation system can affect the surrounding areas in different ways. The effects can be seen around stations or along transportation corridors and in some cases can be seen as a combination of both.  Following the emergence of the notion of environmental quality, the impact of the assessment of urban transportation systems on the quality and value of adjacent areas has become a remarkable topic in urban issues, because it has led to various and sometimes opposite results in different environments. Basically, there is a close relationship between access to transit and urban development. Better access, more mobility options and lower transportation costs are some factors which have made these areas more attractive and more developed.  In fact, access to public transportation can improve accessibility to urban activity and employment centers, retail districts and other facilities.  As a result, a public transit station can affect the quality of urban tissue and eventually the development of the neighborhoods around metro stations, directly or indirectly.  In other words, public transit stations can play an important role in the development of surrounding areas especially from the economic aspect.  This opportunity is very important particularly in blighted urban areas that face many obstacles over the attraction of investment for regeneration and renewal. Therefore, an adequate mechanism to locate and manage public transit stations can propel the low-quality urban tissues where economic problems are rampant to livable and dynamic areas. In a metropolis city like Tehran, public transportation systems especially the metros are being developed rapidly due to serious problems in personal transportation services.  Thus a better understanding of the impacts of metro stations on adjacent areas can help with their development as more purposeful facilities. Also, such impact assessment studies can improve the advantages of developing metro systems, as well as reducing the negative consequences on the urban tissues. On the other hand, this discussion is very specific in Tehran, because unequal environmental qualities between north and south of Tehran and also an unbalanced distribution of resources and facilities over time have made an obvious socio-economic gap in this city.  In fact, socio-economic disparities between northern and southern neighborhoods have transformed Tehran from a sustainable city to a capital with economic polarization and social segregation. This is to the degree that the central and southern regions have gradually changed to low-income areas with low quality urban tissues, and in contrast, the northern regions with high-prices of estates have changed to areas popular to the upper classes.  Therefore, a field study on this issue in Tehran to consider the current socio-economic gap between affluent north and poor south can help draw a comparison between the impacts of metro stations in two different urban areas and subsequently it can assess the role of metro stations in reducing the socio-economic gap in this city. This study seeks answers to these important questions: Which areas of Tehran Metropolis (affluent areas or poor areas) have gained more benefits from opening metro stations? Can we consider the development of metro rail system as a solution to reduce the socio-economic gap between north and south Tehran? The researchers have presumed that the poor areas have received more benefits than affluent areas. Therefore, opening metro stations can improve the economic dynamics of southern neighborhoods of Tehran and subsequently it can integrate the environmental quality of north and south Tehran.  Therefore, this process can reduce the socio-economic gap in Tehran. The accuracy of this hypothesis has been tested with a market study around Shari'ati Metro Station (in northern Tehran) and Shohada Metro Station (in southern Tehran) through measuring changes in housing prices so as to obtain changes in environmental quality before and after opening the stations. Examination of effects of proximity to the metro stations for these two neighborhoods proves that proximity to metro stations has a positive effect on the value of properties in southern Tehran, but a negative effect in northern neighborhoods. In fact, results show that the metro stations have a consistently higher positive impact on the property values which are located in poor areas compared to the affluent areas. Therefore, with the increase in the value of properties in poor neighborhoods on the southern areas and subsequently improving the quality of those areas, Tehran's long-standing gap in socio-economic contexts can be reduced and consequently Tehran can become an integrated city without any segregation and polarization.