This research-in-progress study proposes a research model to analyze the benefits of Enterprise Systems (ES), by using disconfirmation theory as a theoretical basis. We review and extend previous models by including the needs/desires of users as a disconfirmation construct and by separating needs/desires and expectations of the ES from the information provided by the ES. We suggest that both elements have an impact on the overall perceived net benefits of the ES used within an organization. Furthermore, dimensions of equity and attribution theories are explored as a process mediating the effects of these variables on satisfaction with the employee and the organization.