This is an analysis from 1955 to 1995 of the influence of public and private investment on the economic growth of the Basque Country, one of the regional economies that have historically played the most important role in the process of Spain’s economic modernization. The maintenance of a favorable income per capita, the quality of human capital, provision of infrastructures, greater equity in income distribution and a lower rate of poverty, are some of the positive factors that have led to the convergence of the Basque Country with the European average being greater than in the Spanish economy as a whole. In contrast, the fall in private investment has represented a drag on the development of this economy. The research is part of the framework of collaboration between the BBV Foundation and the Valencian Institute for Economic Research (IVIE) for the study of the regional Spanish economy.