The World Bank Doing Business Report (2013) ranked Mauritania 173rd out of 189 countries. Its performance was well below the average of Sub-Saharan Africa. Among the 10 categories analysed by this study, Mauritania performs relatively better in enforcing contracts and registering property permits, whereas starting a business, paying taxes and getting credit are not favourable. The economy is facing several challenges, including heavy state involvement, the lack of competition, corruption and rent seeking. On the one hand, the economy has been increasingly deregulated over the last 15 years, whereas official state ownership gradually declined and trade with international partners has been liberalized. The economic legal environment has been extensively reformed, although lacking specific implementation mechanisms and thus ineffective. On the other hand, the strict regulation imposed by the government on the economy through licensing regime, creates a heavy burden for SMEs. Moreover, an oligopolistic market structure run by few families from a certain tribe makes the market access by the SMEs more difficult. The regulatory and economic structure, in combination, creates clientelistic mechanism, discouraging SMEs’ entrance to the market but instead tempting them to run a business informally. The fiscal regime and the administration of the tax system are also important deterrents.