This study has been motivated by the World Bank's Worm Development Report 1987. That report gave virtually unqualified support for outward orientation rather than inward orientation or import substitution, as if it could be recommended for all conditions and for all types of countries. The claim for the alleged superiority of exportpromoting development strategies as recommended by the World Bank and other export enthusiasts is based less on theoretical analysis than on empirical evidence from extensive crosscountry studies, especially those of Balassa [Journal of Development Economics, May/June 1985, pp. 23-35]. These studies all have indicated that less developed countries (LDCs) with higher export growth have tended to experience higher rates of economic growth, Support for export promotion policies is not universal, however. This study seeks to determine to what extent Latin American and African LDCs have benefitted from their exports during the period 1960-81. From the export-augmented aggregate production function for an open economy, Q = F [L, K, X] where Q is real output, L and K represent labor and capital inputs, and X stands for exports, the following sources of output growth can be derived: