This study examines whether the extent of professional relationships between an audit firm and their client’s CFO influences audit quality. If regulators’ concerns that the relationship that develops over time between an audit firm and their client’s CFO impairs auditor judgment are justified, then we should observe a negative relationship between the length of audit firm’s tenure with their client’s CFO and audit quality. The results suggest that mutual audit firm-CFO tenure is associated with lower audit quality measured by the magnitude of discretionary accruals, the reduced incidence of issuance of going-concern audit opinions for distressed companies, and an increased likelihood of the receipt of an Accounting and Auditing Enforcement Release (AAER) from the US. Securities and Exchange Commission (SEC). These affects are concentrated in a subsample of firms with higher levels of corporate governance concerns. These findings have implications for policies related to audit firm rotation. Specifically, the results suggest that regulators need to consider other relationships underlying audit firm tenure, such as the relationships that form between audit firm and client personnel, when evaluating audit firm rotation policies.