The national solidarity constitutes a concept founder of the State in Tunisia. Gradually replacing the family solidarity, this concept is textually consecrated in the Constitution and in different laws. The reform of the health insurance system under the law No. 2004-71 of August 2, 2004, gives this concept a new dimension and a new width. However, if the law establishes a number of innovative principles, indeed revolutionary in matter of health insurance, the management of health expenditure by national solidarity comes up against enormous challenges in economic and socio-political context of a country like Tunisia. The scarcity of financial means available, the different waiting from the actors concerned with the law (administration, public and private health care, trade unions, insured …) and the fierce resistance of corporatism constitute real obstacles with a true setting concerned of the national solidarity in the medical matter in the country.The difficulty, precisely, of the implementation of Law No. 2004-71 is the most striking manifestations. This difficulty appears in both the establishment of the institutional shutter of the law, and also in the practical modalities of management of health expenditures; modalities envisaged by the law and its various texts of application. In Tunisia, if - through the law No. 2004-71- we are truly in a legal context for renewal of national solidarity in health’s matter, this solidarity finds in this same context a good part of his limits.