Methods and practices adopted by software professionals to develop and maintain software are believed to have significant impact on the project outcomes in terms of development cost and product quality. Disciplined methods and practices are expected to result in better control over the software development process. Even though there is a great awareness that software quality is largely dependent on the way the development process is carried on, there is lack of empirical evidence supporting the effect of software development processes on life-cycle productivity or quality and particularly of the impact of CMM certification on productivity improvement. This paper, using qualitative and quantitative data relative to the software process improvement initiative in which the Italian branch of a multinational software company was engaged from Jan. 1997 to May 2001, investigates the impact of CMM certification on organizational learning. In particular, a knowledge management perspective is adopted to explain the software development process increase in productivity. Data suggest the idea that CMM can effectively support and address knowledge management and learning within a software organization. Organizations using a wellstructured process model such as the CMM can use the process infrastructure it provides for organizational learning. As an organization moves up the CMM levels, predictability is increased, risk is better managed and reduced and organizational learning is enhanced.