Exploratory study of the success factors of rapidly growing SMBs : mythic and relational leadership for contingent and multidimensional management. AbstractSome small and medium-sized businesses achieve incredible success: their financial indicators increase and their employment rate rises for several years without failing. How are these businesses lead? How is their leadership perceived? On which values do they rely? How can their strategy be described? What is their human resources policy? These are among the many questions we will attempt to examine. Indeed, one can be intrigued by the success of such businesses, as keeping afloat is not always easy. The very competitive environment in which these enterprises evolve can cause them to lose everything they had gathered in just a single day. In our challenging socio-economical context, where financial success remains fragile and larger companies are forced to lay off parts of their workforce, small and mediumsized businesses are a significant source of employment. They are more and more involved in the economic revival.It is therefore not surprising that many studies have examined the questions of business growth, performances or efficiency (Lescure, 1991 ;St Pierre, Janssen, Julien, Therrien, 2005 ; Colot, 2008 ; Witmeur, 2008a). The success of a company rests on many factors. Among these, leadership seems fundamental but is actually far from alone; other elements play their part, such as strategic orientation and partnerships. In order to understand these exceptional cases, we must consider a whole series of factors.Nowadays, when mention is made of a situation of growth, one can be tempted to visualize a fierce race driven only by financial results. As we will observe, this theory needs to be reviewed. Among the companies that have been interviewed, the ones which have the most significant growth are those that grant much importance to the human and relational factors.They organize the various facets of business management according to their specific situation.Situations are complex and, to a certain extent, different from one another. Our purpose was precisely to understand this complexity.