The study of Tunisian Small and Medium-size Enterprises (SMEs) difficulties to access to funds shows that these enterprises experience a “banking integration deficit” that can be explained by credit rationing theory. The reluctance of Tunisian banks to become involved in SMEs' financing is largely explained by the structural and financial characteristics of the Tunisian banking system whereof of the dominance of commercial banks results in a limitation of competition on the financing cost. It is also explained by the weaknesses experienced by Tunisia as regards the sharing information and the creditors legal protection throughout the financing transaction.The empirical verification of Tunisian SMEs' credit rationing on the Tunisian bank credit market is founded on an estimate of a disequilibrium model on the basis of a panel data set of 1760 Tunisian SMEs over the period 2001-2006. Results show that Tunisian SMEs, dependent on bank credit, seek to avoid the call for this source of financing every time they experience an increase in their internal resources or have recourse to trade credit. The very strong risk aversion of banks makes the credit supply decision mainly dependent on real guarantee, and results to an average proportion of 90% - partially or totally - credit rationed enterprises.