This paper discusses the sources of product innovation in young innovative companies (YICs), here defined as firms engaged in product innovation and with less than 8 years of activity. In particular, we look at in-house and external R&D and at the acquisition of external technology in its embodied and disembodied components. These input–output relationships are tested on a sample of 2713 innovative Italian firms. A sample-selection approach is applied to study both the determinants of product innovation and the factors affecting the intensity of innovation.