The revised 8th eu directive restricts the provision of non-audit services to audit clients. The reason behind this is the idea that the simultaneous provision of audit and non-audit services to clients may endanger auditor independence. This is also indicated by previous research on the provision of non-audit services to audit clients. There is however little evidence on the perceptions of supervisory board members regarding this issue. This study therefore investigates the perceptions of supervisory board members on the effect of the simultaneous provision of non-audit services and audit services on auditor independence in germany. The results show that the provision of non-audit services is perceived to have a negative effect on the independence of auditors. Furthermore, when we distinguish between various forms of non-audit services, human resource consulting is perceived to have the most influence on auditor independence. Finally, confidence in auditors and experience affect the perceptions of supervisory board members regarding the effect of non-audit services on auditor independence.