While the act of faith approach to management development assumes that training and development will improve performance, and that attention to the people factor will give organizations a competitive advantage, there has been little systematic study of the business benefits of management development. The extent to which competence-based management development made identifiable improvements to individual, organizational and business performance was examined in sixteen organizations using an indepth embedded case-study protocol developed following the preparatory work of an expert group convened by the Department for Education and Employment (DfEE). Interviews were conducted with senior strategic managers, line managers and members of management work teams, and triangulation was sought with documentary evidence. Case reports were validated with the organizations, then evaluated and ranked by an independent consultancy not involved in the fieldwork. The results provide support for attributing business benefits to management development, particularly in relation to individual and business performance. The performance improvements were found to be most significant where management development is linked with organizational strategy and where Human Resource Development (HRD) systems and processes adopt the management standards developed by Management Charter Initiative (MCI).