Stevenson (1983) holds that entrepreneurial management, defined as a set of opportunity-based management practices, can help firms remain vital and contribute to firm and societal level value creation. While his conceptualization has received much attention, little progress has been made because of a lack of empirical tools to examine his propositions. This article seeks to resolve this by describing a new instrument that was developed specifically for operationalizing Stevenson's conceptualization. After two pre-tests, the instrument was tested full scale on a very large (1200+ cases) stratified random sample of firms with different size, governance structure, and industry affiliation. The results show that both in the full sample and in various sub-samples it was possible to identify six sub-dimensions with high discriminant validity and moderate to high reliability, which represent dimensions of Stevenson's theoretical reasoning. We label these Strategic Orientation, Resource Orientation, Management Structure, Reward Philosophy, Growth Orientation and Entrepreneurial Culture. We were further able to show that these dimensions only partly overlap with ‘Entrepreneurial Orientation’, the hitherto best established empirical instrument for assessing a firm's degree of entrepreneurship. Our instrument should open up opportunities for researchers to further evaluate entrepreneurship in existing firms. Copyright © 2001 John Wiley & Sons, Ltd.