This study aims to analyze the influence of internal control system and internal audit performed by the government on the prevention of corruption mediated using accrual-based accounting. The research is descriptive and causal using survey method by gathering questionnaire from the whole population. There were 102 respondents who are civil servant employees of the Government of North Sumatra Province. For data analysis, the study used PLS SEM aided by software program SmartPLS version 3.0. The results of this study revealed that the government internal control system has a positive effect on the implementation of accrual based accounting, while internal audit has no effect on the accounting implementation. For implementation of accrual-based accounting has a positive effect on prevention of corruption. Likewise, the government internal control system has a positive effect on corruption prevention and also internal audit positively affects the prevention of corruption. The government internal control system influences the prevention of corruption through the implementation of accrual based accounting while the internal audit has no effect on the prevention of corruption through the implementation of accrual-based accounting.