The human capital model is used as a framework for analysing the determinants of incomes of a sample of Canadian professions. The conventional earnings function is augmented by inclusion of measures of restrictions on competition applied by some of the professions. The data base consists of information developed from provincial licensing laws, some original sample survey data and published tabulations of the 1971 Census of Canada. The results suggest that both restrictions on professional advertising and restrictions on fee competition contribute significantly to professional incomes. The attempts to measure the separate contribution of restrictions on entry and on interjurisdictional mobility were unsuccessful.