The concepts of market orientation and innovation and their interrelationship with business success have been explored from a number of perspectives. However, research in this area has not explored the differences between start-up and mature companies. The research study acquired data from over two hundred Chief Operating Officers (CEO’s) and Managing Directors from both start-up and mature companies. The results illustrate the differences in both types of company and reveals new insights with regard to market orientation and its constituent elements and its relationship with both incremental and radical innovations. Key research results are that strong competitor orientation, a key ingredient of market orientation, has positive relationship to incremental innovation for start-up companies but it is contra productive for mature companies. In mature organizations a strong customer orientation is associated with radical innovation.