This research has purpose to know Sistem Kliring Nasional Bank Indonesia's implementation and internal control that PT. Bank X (Persero) Tbk. Kantor Cabang Utama Mojokerto uses to reach company's goals. Model research type's descriptive with qualitative approach. The researcher gets primary data from interview with clearing's staff, secondary data from documents that they use. The research concludes that clearing's implementation has good enough,it's because almost all of the clearing implementation's appropriate to Sistem Kliring Nasional Bank Indonesia; carrying out of debit and credit clearing system, participation in 2 cycles of clearing (delivering,return), using warkat and clearing document,checking them before processing,etc. Some things which isn't approprite to Sistem Kliring Nasional Bank Indonesia and cause clearing rejection are accepting, processing bilyet giro before effective-date, saldo rekening doesn't enough, uncompleted fulfilling formal requirement, rekening number the money transfer to had been closed, signature isn't same with specimen, etc. The mistakes happened because of human errors.According to the errors that happened, the researcher only suggest to clearing's officer and customer of clearing to increase the carefulness of checking and admission filling in order to minimization errors happen. Internal control of PT.Bank X (Persero) Tbk.Kantor Cabang Utama Mojokerto could reach the goals of internal control.