Today’s rapid turmoil in economy caused by globalization and changes in world, has forced, leaders and managers in public institutions as well as private organizations to adapt and change their organizations’ cultures with their own management systems and styles. Different situational management theories and approaches are scrutinized in this study. Literature review focuses on management styles. This paper investigates classic approaches, management boundary conditions and possibilities that these approaches can give to leaders and managers. The ontology for management style was created in this study, and gives the preliminary frame for university hospital leaders when inspecting possibility to move to Lean management. This article points out to future research needs.