Determinants of Income Distribution. — This article is intended to prove that the various macro-economic “theories of income distribution” appear to be systematic explanations only because the method of forming models — i. e. the grouping together of private economy elements and their relations to macroeconomic aggregates — obscures important determinants of distribution. This hypothesis is proved in two steps: first, it is shown that the two most important elements of the various distribution models — macro-economic production function on the one hand and macro-economic consumption function on the other — in the way they are usually employed, imply assumptions of constancy which lead either to logical inconsistency in the respective distribution theory or to empirical meaninglessness. Second, it is shown by means of an enlarged two-goods-two-factors Solow model that the various macro-economic distribution theories should be integrated so as to include all the various determinants of distribution. Even the enlarged Solow model cannot be regarded as the foundation of an empirically meaningful distribution theory. Reflection on how to improve this model brought out the necessity of examining the quantitative importance of each one of the various determinants of income distribution. This examination, undertaken for the German Federal Republic, has shown that the influence of demand on income distribution, during the period from 1950 to 1967, was comparatively small.