BACKGROUND Sex differentials in occupational composition have been studied in the past (Knudsen 1969; Gross 1969). The technique has primarily dealt only with the perce~tageof males and females in specific occupational categories. A recent study of sex differentiation by occupational categories of census data for white females in 66 standard metropolitan statistical areas (SMSAs) in the United States found rather wide differences (Martin, Poston 1972). If SMSAs vary widely in sex differentiation of occupational composition, how wide is the variation along the rural-urban dimension? What are the effects, going from central city through various sizes of urban areas, to the rural-farm areas of the United States in the study of occupational differentiation? Drawing on the work of Durkheim (1974) one would expect more densely settled places to be characterized by greater occupational differentiation regardless of sex, with a larger spread of men and women thoughout various occupational categories. Between-sex differences would also be expected to vary by size of place. A lower degree of sex differentiation in occupational composition should be found in larger places, due partially to the opportunity for females to move into previously male-dominated occupations. Lacking this occupational opportunity structure, females in smaller places, or in rural areas would still be employed more extensively in sex-typed occupations. Smaller places and rural areas exhibit greater sex differentiation in occupational composition.