This paper reports on the theoretical development and empirical validation of a measurement instrument for three information technology (IT) core capabilities in an electronic commerce context. The instrument is based on the work of Feeny and Willcocks (1998) and includes the capabilities ‘information systems (IS)/IT governance’, ‘business system thinking’ and ‘relationship building’. It was validated using a sample consisting of 179 respondents, all of whom were IT managers or chief information officers. The results demonstrate that the constructs are reliable (α coefficients < 0.8) and valid. A confirmatory factor analysis on the data set yielded a moderately acceptable model fit. The model also demonstrated highly significant factor loadings (p < 0.001). The paper shows that a respecification of a competing model in which IS/IT governance is split into ‘business IT strategic thinking’ and ‘IT management’ provides better measures of fit. The paper concludes that the core capabilities of IT departments are useful constructs for incorporating into future research. They are successfully able to predict behaviours that have relatively little overlap. Recommended further research includes the relationship between capabilities and governance structures as well as further investigation into how IT core capabilities are formed and strengthened in organizations. © 2001, Association for Information Technology Trust. All rights reserved.