This research looks into how Mandatory Internal Control Audits (MICAs) affect companies’ efforts to avoid paying taxes. We focus on when MICAs were gradually introduced for certain companies in China. By comparing different groups of companies, we found that those subjected to MICAs significantly reduce their tax avoidance after the audits are in place. We also found that this effect is more noticeable in companies operating in environments where information is not very transparent. Importantly, MICAs help decrease the overall tax risk for companies. In conclusion, this study adds to the discussion about whether MICAs are worth the costs.