Le risque de crédit présent dans tous les contrats financiers constitue la principale source de pertes pour les banques et les institutions financières au Liban. Le secteur bancaire libanais connaît en matière de crédit une évolution sans précédent conséquence de trois mutations principales : Un rôle sans cesse croissant des marchés financiers dans le système financier international; l'émergence au sein des banques de nouvelles techniques quantitatives de management des risques de crédit; une réglementation bancaire en cours de changement / The Credit Risk which existed in all financial contracts constitutes the principal resource of loss for the banks and financial institutions in Lebanon. During the last years, the measure and the risk management have grown an importance in the banking industry, causing a development of new tools especially for the Corporate. The banking authorities, who are realizing this evolution, have decided to reform the regulation of the Capital Adequacy. Thus, the reform of Basle II proposes new allocation of assets based on better evaluation of risk. Basle II incites the banks to be provided by performing internal system of scoring of all their customers (Retail and Corporate).For this purpose, the Lebanese banking sector has shown, in matters of credit, an unprecedented evolution, consequence of three principal changes:a growing role of financial market in the international financial system; an emergence in the middle of banks of new quantitative techniques of Management of Credit Risk; a banking regulation in progress of change.This thesis have for objective to present all the different risk, take stock of their management in the midst of Lebanese banks and to provide a lighting on the new track of development viewed for these banks in order to come from the high risk.