State governments have begun to introduce various eprocurement tools to improve inefficient and ineffective procurement management; however, few empirical studies have documented the diffusion of e-procurement. This study uses data collected from state procurement agencies to examine which e-procurement tools state governments are using as well as to explore what factors affect the adoption of these tools. This study confirms that simple innovations are more rapidly diffused than those that are technically or legally complex. State governments that are more likely to adopt e-procurement tools tend to be larger, managerially innovative, and to have a strong centralized procurement office. Overall, e-procurement is promising technology, but managerial and technical challenges still remain.