This paper aims to identify and evaluate the expectations and perceptions of customers from grocery stores of the Fifth District of Southern of the city of Merida, Yucatan, in specific the area known as" Santa Rosa", through the Service Quality Model (SERVQUAL) of Zeithalm, Parasuraman and Berry (1993). The SERVQUAL model was adapted specifically to the type of stores and customers to determine if the quality of service results in a competitive advantage to prevent the increasing closure of the grocery stores in the local market, which is opposite to the increase of the opening of convenience stores and the arrival of large supermarket chains. The study presents a non-experimental research that focuses on District V in Southern area of Merida, which represents the largest concentration of grocery stores in the city (after the downtown), and where early growth of convenience stores was observed. Final results of the analysis of differences between the expected and perceived service quality through the dimensions proposed by Zeithalm et al.(1993) are presented. The results show that in general, customers expect more quality from grocery stores, but are not too far off from achieving their expectations. Therefore, the larger dimension is empathy.