Towers, Perrin, Forster & Crosby, international management consultants, and Cresap, McCormick and Paget, general management consultants, will merge operations on Jan. 1. Cresap, McCormick & Paget will become the general management services division of TPF&C's consulting division.

Both organizations have Washington offices. John W. Fisher, present Washington manager of TPF&C, which has 35 offices worldwide, will head the merged offices here. Fisher is a vice president and director of TPF&C. The present manager of CMP's southeastern region office in Washington, Louis H. Knapp, will head the general management services division within TPF&C here.

Knapp said Cresap, McCormick & Paget, which has four regional offices in this country and one in Europe, will retain its name for some time after the merger. The new division will continue to operate under the current CMP management structure. Plans are not yet firm for the physical consolidation of offices and personnel here.

Projected 1983 revenues for the combined firm are approximately $200 million. The merged consulting organization will be one of the largest in the world, specializing in human resource, actuarial and general management services.

Towers, Perrin, Forster & Crosby was incorporated in its present form in 1934, with operations divided into a management consulting division and a reinsurance division. Cresap, McCormick & Paget was founded in 1946 and incorporated in 1969. It is owned by practicing members of the firm.

TPF&C is based in New York and has a total staff of more than 1,800. CMP also is based in New York and has 160 employes, approximately 100 of whom make up the professional consulting staff. Their regional offices are located in Chicago, New York, San Francisco, Washington and London.