IT Audit per IDW PS 330: Requirements and Preparation
Martin Müller
February 4, 2026
7 min read
The IT audit per IDW PS 330 is an integral part of the annual audit. Auditors examine whether a company's IT systems ensure the regularity of bookkeeping. For many companies, this audit is a black box. Here you will learn what to expect and how to prepare.
What IDW PS 330 Examines
The standard examines the IT environment across multiple dimensions: IT strategy and organization – Is there a documented IT strategy? Are responsibilities clearly defined? IT infrastructure – How are servers, networks, and workstations secured? Is there patch management? IT applications – Are accounting-relevant applications correctly configured? How are changes tested? IT-supported business processes – Are automated controls implemented and effective? IT monitoring – Is there monitoring and logging?
Common Weaknesses in Practice
From my experience auditing large and medium-sized companies, I know the typical weaknesses: missing or outdated IT documentation, inadequate authorization concepts – too many users have admin rights, lack of separation between development, testing, and production environments, no documented change management for software updates, and incomplete data backup concepts. In the worst case, these deficiencies can lead to qualifications in the auditor's report.
How to Prepare Optimally
Start preparing at least three months before the audit. Document your IT landscape, authorization concepts, and change management processes. Perform a gap analysis: where are you today, where do you need to be? Prioritize fixing critical weaknesses. And prepare a point of contact who can answer all IT-related questions for the auditor.
My Experience at the Intersection of IT and Auditing
With my background in auditing and IT, I understand both sides. I know what auditors want to see and how to set up your IT systems accordingly. Whether audit preparation, supporting the IT audit, or remediating identified deficiencies – I support you competently and efficiently. Schedule a free initial consultation.