The main aim of the study was to determine factors for supermarket performance in Dar-essalaam. The study was done on five supermarkets (Wanlong, Game, Choppies, TSN and Maisha supermarket) in Dar-es-Salaam, Tanzania. The study was guided by six research objectives namely; to determine the trend of current and previous sales of supermarket in Dar-es-Salaam, to identify the extent to which internal factors affect Supermarket performance, to determine the extent to which the external factors affect Supermarket performance, to what extent do the capacities of the resources relate to Supermarket performances, to establish number of supermarkets in Dar-es-salaam and to examine the relationship between Capital, Organization strategy, Customer services, Management skills, Work environment, Economic condition, Competition, Technology, Government regulations, firm size as independent variables and supermarket performance as dependent variable . The descriptive design was employed in order to analyze the topic thoroughly. There are more than 30 supermarkets in Dar-es-Salaam but the study used only 5 supermarkets and I interviewed 100 respondents. Non-probability sampling technique was employed. Regression analysis was employed to analyze dependent and independent variables. This study was used secondary data and questionnaires which were collected from the 5 selected supermarkets in Dar-es-Salaam. Data were analyzed using statistical packages on social sciences (SPSS). Generally, the study reveals that a mean of 3.94 on capital and a mean of 4.17 on technology as the most internal factor affecting supermarket performance while a mean of 3.55 on competition as an external factor affecting the performance of supermarket to a great extent. Also, the study shows a mean of 1.47 on capital as the most important resource for the performance of supermarkets and a mean of 2.42 on technology as the important factor for the performance of supermarket while a mean of 2.14 on skilled personnel. Also, the study reveals that supermarkets in Dar-es-Salaam are very few which makes them unable to generate stronger competitive capability. The study used regression analysis to show the relationship between Capital, Organization strategy, Customer services, Management skills, Work environment, Economic condition, Competition, Technology, Government regulations, firm size as independent variables and supermarket performance as a dependent variable. The study found that technology, organization strategy, government regulation, and management skills have a significant relationship with supermarket performance while capital, team style, working environment, economic condition, and firm size has no significant relationship with the supermarket performance in Dar-es-Salaam. The study recommends further research on the determinant of supermarkets in other regions of Tanzania. Also, the numbers of selected supermarkets were small (only 5 supermarkets) further studies could increase the number of supermarkets. Lastly, further studies can be used to establish the actual relationship between the variables.