Purpose – This paper aims to examine the effect of audit partner tenure (PARTEN) on client managers' accounting discretion. Design/methodology/approach – The authors contend that, when a new audit partner is from the same audit firm as the outgoing audit partner (audit partner rotation), audit quality increases because the new audit partner brings “fresh eyes” to the engagement. Findings – The results confirm this conjecture. The authors find that, in the initial years of tenure of a new audit partner, client managers' accounting discretion decreases when the new partner is from the same audit firm as the outgoing partner. However, when the new audit partner is from a different audit firm as the outgoing partner (audit firm rotation), it is found that client managers' accounting discretion increases in those initial years. Originality/value – The results provide support for recent legislation in the US restricting audit PARTEN and should be of interest to other regulatory bodies contemplating mandatory audit partner rotation.