We look into the interaction of the project manager’s leadership style with project type, and their combined impact on project success. We aim to show that different leadership styles are more likely to lead to a successful outcome on different types of project. A recently developed integrated model of intellectual, emotional and managerial competence (IQ, EQ, MQ, respectively) is used to identify project managers leadership styles. A web-based questionnaire was used to determine the leadership style of project managers and relate that to the success of their most recent projects. These are related to project types, using a recently developed categorization system for projects. These quantitative results are validated against qualitative results obtained using semi-structured interviews of managers responsible for assigning project manager to projects.