T HIS paper describes patterns of occupational mobility for men in selected professional statuses. The data are for 654 sample cases of white males 25 years old and over in the four cities of Chicago, Los Angeles, Philadelphia and San Francisco in January, 1951, who held a professional job at some time during the 1940 to 1950 decade, and who worked one month or more in 1950.1 The 654 sample cases represent an estimated 240,063 white males in the four cities combined.2 The growth of modern cities and states with the industrial revolution has had a profound influence upon the professions. The increase in complexity of the division of labor, in particular, has had its counterpart in the professions. Sir Alexander Morris Carr-Saunders differentiates four major types of professions in modern industrial states.3 The old established professions are founded upon the study of a theoretical structure of a department of learning which is used in the practice of the art founded on it, and the members of the vocation feel bound to follow a certain mode of behavior. Religion, law, medicine, higher education and aesthetics are associated with the old established professions. The new professions have their own fundamental studies upon which their art is founded. Chemists, engineers, natural and social scientists are examples of the new professions. By way of contrast, the semiprofessions replace theoretical study of a field of learning by the acquisition of precise technical skill. Technical practice and knowledge is the basis of such semi-professions as nursing, pharmacy, optometry and social work. There are, also the would-be-professions, where members aspire to professional status. Familiarity with modern practices in business and government generally distinguishes this group. Personnel directors, sales engineers, business counselors, funeral directors and institutional managers are examples of vocations where members aspire to professional status. A fifth group, the marginal professions, is included in this study for comparative purposes, although it is not identified by Carr-Saunders. The category is made up largely of those who perform technical assignments associated with professional assignments, e.g., medical and laboratory technicians, testers, illustrators, draftsmen, interpreters and inspectors. The mobility of members of each of these groupsis compared below. A basic objective of this study is to describe occupational mobility patterns of men in five professional status groups, and to analyze a few factors associated with these mobility patterns. A number of studies of mobility made during the past decade provide a measure of occupational mobility in the work force based on a longtiudinal view of job or work histories.4 This study em*Revised version of paper read at the annual meeting of the American Sociological Society, September, 1954. IThe data were obtained from the work history schedules of the Occupational Mobility Survey sponsored by the Science Research Council and conducted in co-operation with six university centers and the U. S. Bureau of the Census on behalf of the U. S. Department of the Air Force. See Gladys L. Palmer, Labor Mobility in Six Cities, New York: Science Research Council, 1954, for a description of the study design. All persons coded 0 in the U. S. Bureau of the Census occupational code are included in the analysis. 2 The raw data come from four separate samples. For each city estimates were made separately based on the weights for that city. The proportion of persons who held a professional job at some time during the decade is not the same for each city. The percentage for each city in this study is: Chicago, 24 per cent; Los Angeles, 32 per cent; Philadelphia, 21 per cent; San Francisco, 23 per cent. 3 See Alexander Morris Carr-Saunders, Metropolitan Conditions and Traditional Professional Relationships, in The Metropolis in Modern Life, edited by Robert M. Fisher, New York: Doubleday and Co., 1955, pp. 280-81. 4For example, see Seymour M. Lipset and Reinhard Bendix, Social Mobility and Occupational Career Patterns, Parts I and II, American Journal of Sociology, 57 (January, 1952), pp. 366693