Based on the results of the Recensement général des entreprises (enterprise general census) carried out in Senegal in 2016, this article analyzes the preponderant role of SMEs in the Senegalese economy. Indeed, SMEs represent 99.8% of all economic units inventoried. This article draws on a series of major theoretical frameworks to define the five fundamental characteristics of Senegalese SMEs. Then we analyze these SMEs on the basis of hierarchical financing theory, proxemics theory and trade-off theory to draw their portrait. We also highlight the issue of harmonization in the definition of SMEs in the country. We conclude with interesting perspectives on the correlation between these five characteristics.