Banks and firms, two institutions on which health is interdependent. In the traditional form of financial intermediation, the bank functions on the basis of of the deposits collected and the credit distributed. For the companies, especially SMEs, the banking financing is considered as the most important source of financing of their investments. The banque-entreprise relation presents a double interest. The company seeks to guarantee the immediate and the future financing, whereas the bank seeks to be refunded in the future. The economic importance of the company like productive agent, on the one hand and the contribution of the credit institutions in the financing of the firms, on the other hand, return being studied of relation banks-entrprise, its determinants and its effects on the firms performance. The value of this book is that it allows, with the companies to well choice the number and the duration of their banking relation making it possible to maximize moreover their performance.It contributes for the good decision-making of financing the firms on behalf of the banks and this within the framework of a bank relationship.