Success of an e-business rests on many factors. One of the important contributors is trust. Online trust is one of the key obstacles to vendors succeeding on the internet medium; a lack of trust is likely to discourage online consumers from participating in e-commerce. Thus, building trust among customers is one of the challenging issues for on-line service providers. On the other hand, trust, itself is influenced by many factors. This study elaborates on the importance of customer trust in ecommerce. Among the factors affecting e-trust, this study focuses on two factors: "internet shopping experience" and "level of customer knowledge of information usage and security mechanisms". An experimental study has been conduced in the Iranian e-market. Findings of the study confirm the impacts of both of the above factors on the level of Iranian e-customers trust.