This research analyzes the effects of Information Technology (IT) on Supply Chain Integration (SCI) through ERP mediator by proposing a conceptual model among these components. We also hypothesize that three constructs of IT influence on enterprise resource planning (ERP) success and one construct of ERP success influences on SCI. To clarify the relationships among the constructs, structural equation model (SEM) is conducted to examine the model fit and seven hypotheses. The data was collected from three Iranian firms through questionnaire with 23 questions adopted by past researches. The results confirmed that top management support of IT and employees’ general IT skills factors of IT enhance ERP success, and ERP success positively influences on Supply Chain Integration, so these two IT factors influence Supply Chain Integration through ERP success. Our data unsupported negative impact of satisfaction with legacy IT system on ERP success.