The objective of this research is to analyze the effects of Ara store entry on small traders in the city of Cartagena. This group represents a channel of growth opportunities for the city's commercial sector, in contrast to large-area formats such as Ara stores in the especially strata 1, 2 and 3 neighborhoods throughout the city. From this perspective, we seek to establish the factors of competitiveness, marketing and business management that have allowed these small entrepreneurs to remain in the market. The research is of a descriptive type of cross-section, through the application of survey to traders, allowed to characterize the most relevant variables related to the effects of the entry of Ara stores to the city of Cartagena. The study showed that with the entry into the market of Ara stores to the city of Cartagena, there were significant changes in market dynamics, because there are many factors involved in commercial activities and that it is easily affected by changes in market conditions. In the same sense it is the customers who choose the site, where they will make purchases of the goods and services they are needing, based on which the site to choose provides them with the maximum benefit, in terms of quality, attention and prices.