The concept of entrepreneurial alertness is a central component of Kirzner’s economic theory of entrepreneurship and the market process (Kirzner, 1973; 1979; 1985; 1992). As such, it has attracted considerable interest from economists and entrepreneurship scholars alike. To date, however, empirical research on alertness has proved equivocal (cf. Craig & Johnson, 2006; Kaish & Gilad, 1991), if not altogether disappointing (cf. Busenitz, 1996). As a result, scholarly work on entrepreneurial alertness remains mostly conceptual (e.g., Gaglio & Katz, 2001; Minniti, 2004; Yates, 2000), with very few empirical studies focused on the antecedents, components, and consequences of the construct as observed ‘out there in the field’. In this paper, we begin validation work on a new measure of the entrepreneurial alertness construct.