The dimensions and determinants of positional inequality in the American occupational structure are examined. Using data from the 1972-1973 Quality of Employment Survey, dimensions of occupational differentiation with multiple discriminant analysis are constructed and a causal model is developed to represent the interrelationships of those dimensions. It is found that the differentiation of intrinsic occupational rewards is attributable largely to the educational and task requirements of occupations, while union, supervisory, and organizational resources available to occupational groupings are the strongest determinants of the differentiation of extrinsic rewards. Implications of these findings for functional and conflict theories of inequality in occupational rewards are discussed. (Author/HD)