The Chartered Management Institute and the Institute of Management Consultancy have announced plans to merge.
The merger, ratified in a ballot of IMC's 4,200 members, is expected to be completed by next January.
Under the terms of the merger each institute will retain its own brand identity and the IMC will operate as a separate directorate within the larger 74,000-member Chartered Management Institute.
Calvert Markham, president of IMC said there was a natural alliance between the two bodies.
Mary Chapman, chief executive of the Chartered Management Institute, said that the new body would mean greater benefits for its members.
"As a combined entity with IMC, we will be in an even stronger position to develop respected, influential and professional leaders and form a community of practitioners committed to improving corporate performance," she said.