This paper presents a model of Schumpeterian competition in alternative technological regimes. It extends the work of Nelson and Winter, using a Markov model of a single industry where firms produce a homogeneous product and compete primarily through productivity improvements. The model considers both innovation and imitation as competitive strategies, with innovation being the major competitive weapon. Technological opportunities are exogenous, and firms must invest in costly and uncertain innovative efforts to take advantage of them. The model also incorporates an entry model to account for the role of new entrants in innovation. The paper discusses the concept of technological regimes, which are characterized by different sources and processes of innovation. It contrasts two Schumpeterian regimes: one where innovation is driven by entrepreneurial activity and another where innovation is routinized and driven by large firms. The paper argues that the difference between these regimes can be traced to differences in the technological regime in which development takes place. The model is used to simulate two scenarios of industrial development, one resembling "early Schumpeter" and the other "late Schumpeter" patterns. The simulations show that the simulated histories differ in numerous respects that are reminiscent of the difference between Schumpeter's two accounts. The paper concludes that the concept of technological regimes is a promising approach for understanding the sources and processes of innovation. It also suggests that the role of entrants and established firms in innovation is an important area for further research.This paper presents a model of Schumpeterian competition in alternative technological regimes. It extends the work of Nelson and Winter, using a Markov model of a single industry where firms produce a homogeneous product and compete primarily through productivity improvements. The model considers both innovation and imitation as competitive strategies, with innovation being the major competitive weapon. Technological opportunities are exogenous, and firms must invest in costly and uncertain innovative efforts to take advantage of them. The model also incorporates an entry model to account for the role of new entrants in innovation. The paper discusses the concept of technological regimes, which are characterized by different sources and processes of innovation. It contrasts two Schumpeterian regimes: one where innovation is driven by entrepreneurial activity and another where innovation is routinized and driven by large firms. The paper argues that the difference between these regimes can be traced to differences in the technological regime in which development takes place. The model is used to simulate two scenarios of industrial development, one resembling "early Schumpeter" and the other "late Schumpeter" patterns. The simulations show that the simulated histories differ in numerous respects that are reminiscent of the difference between Schumpeter's two accounts. The paper concludes that the concept of technological regimes is a promising approach for understanding the sources and processes of innovation. It also suggests that the role of entrants and established firms in innovation is an important area for further research.