Drawing a framework from institutional and legitimacy theory, supplemented by concepts from the accounting literature, this study uses longitudinal cross-sectional and cross-national data on over 500 firms listed in the Dow Jones Sustainability Index (DJSI) to empirically test whether these firms are strategic in their philanthropy as indicated by their measurement of the impact of their philanthropic activities along three dimensions - society, business, and reputation and stakeholder satisfaction. It is predicted that the variables' company size, amount of philanthropic expenditure, region and industry influence the extent to which the various impact dimensions of philanthropy are measured. Though unexpected considering the lack of common practice in impact measurement, it is found that between 62 and 76% of the DJSI firms measure some sort of impact of their philanthropic activities, mostly impact on society and impact on reputation and stakeholder satisfaction. The number of firms that measure impact increases over the years and so does the number of firms that measure multiple dimensions of impact. Consist with our predictions, we find that larger firms and firms with relatively higher philanthropic expenditures are more likely to measure impact. Moreover, firms in the financial sector and firms from Europe and North America are also more likely to measure impact of their philanthropic activities.