This study examines the impact of economic integration on growth by constructing an economic integration index based on average Most Favoured Nations tariffs and the level of regional cooperation for the three trade blocs of Eastern and Southern Africa, namely COMESA, EAC and SADC. Furthermore, the study confirms this relationship using an intra-regional trade intensity index for each of these trade blocs. Based on extreme bounds analysis and drawing on the neoclassical and endogenous growth theories, robust conditioning variables for economic growth are identified. System Generalized Method of Moments estimation technique for panel data is employed which eliminates; the inconsistencies arising from omitted variables; measurement errors; endogeneity bias; unit root effects in the choice of instruments; and attenuates effects of differencing that plague most of the empirical work in the literature. The study finds that economic integration and trade, separately and jointly, have a positive and significant impact on growth.