The importance of diffusion of technology for economic growth has been emphasised by economic literature. Much of the recent work on economic growth can be viewed as refining the basic economic insights of classical economists. The recent debate on the determinants of output growth has concentrated mainly on the role of knowledge, typically produced by a specific sector of the economy. This paper attempts to examine the role of diffusion and technical change (research and development) on output growth according to Schumpeterian lines. Following on the Schumpeterian tradition, this paper starts from the recognition that there are two main patterns of innovations: the first one is the creative destruction pattern and the second one is a creative accumulation pattern. Also, it emphasizes the role and the impact of the diffusion of technology in the inter-country and international economic contexts. Finally, it attempts to analyze the empirical implementation of the diffusion models through epidemic, probit analysis and technological substitution models.