This paper examines the empirical validity of the Cobb- Douglas (CD) Model of Economic Growth for 31 Sub-Sahara African (SSA) countries. We made use of labor and capital shares of income coefficients estimated from aggregate production functions for both Kenya and South Africa. Using the estimated coefficients of factors share of income, we decomposed the sources of economic growth in the 31 SSAs as a group and, in each of the countries within the group for the periods 1975–2008 and, 1995–2008. Our findings indicate that from 1975–2008, about 68 percent of SSA’s growth is accounted for by accumulation of physical capital, 28 percent by labor and, 3 percent by growth of total factor productivity. Among SSAs, the highest growth rate of GDP and, capital accumulation occurred during the period 1995–2008.