Knowledge Management (KM) becomes the tools for gaining the competitive advantages. But, its implementation cannot be confirmed giving any significant impact to the organization. This research is aimed to evaluate the impact of Knowledge Management System (KMS) implementation toward system administrator, the active user of the KMS in Bank Indonesia. This research is also aimed to determine the capability maturity level of the KM. This research is measured based on employee's responses to a questionnaires based on KM capability maturity indicators designed by Elmi Achelia. Then the question is categorized in three-dimensional effects, namely employee learning, employee adaptability, and employee job satisfaction. Recapitulation data is processed using partial least square approach using SmartPLS tools. Later, the data is used to calculate weights to determine the maturity level of the organization. As a result, the implementation is proven to give significant impact on the tree dimensions. In addition, based on the research results, Bank Indonesia has evaluated its capability maturity of KM and it stands on level 1.