Information systems infrastructure (ISI) was ranked as the most important issue in a 1994-1995 study of key issues in IS management (Brancheau et al. 1996). Yet, to date, little theoretical and empirical work has been done in this area. This study attempts to reconceptualize the ISI construct and its measures. Drawing from the literature, this study envisions ISI as a base of shared technological, human, and organizational capabilities that provide the foundation for business application systems in the form of services to a range of users. A measure of ISI capability was developed and operationalized through a self-administered mail survey sent to IS executives across the country. A factor analysis revealed that ISI was a multidimensional construct consisting of three underlying dimensions: technological, human, and organizational. A research model was proposed to assess the main impact of ISI on business effectiveness and the moderating effect of information intensity. Five selected business effectiveness variables were time and cost reduction in systems development, system availability, user satisfaction, improved financial performance, and outstanding financial performance. The results of hypotheses testing revealed that human capability was significantly related to system availability and user satisfaction, and organizational capability significantly influenced all business effectiveness, except system availability. Surprisingly, no significant impact of technological capa- bility on any business effectiveness variables was detected. For the moderating effect, the more information intensive the organization, the greater the impact of ISI on time and cost reduction in systems development and outstanding financial performance. This study concluded that ISI capabilities contribute to business effective- ness. Future research should focus on refining the proposed research model using additional data or different data collection techniques.