This report aims to provide guidance on compliance with the legal requirement to undertake a critical examination of x-ray equipment used in diagnostic radiology. An update of the previous guidance (IPEM Report 79) was required due to a change in legislation and major advances in x-ray equipment since the publication of that report. The report is intended for all those who have duties under the regulations - those who are responsible for ensuring a critical examination is undertaken, those performing critical examinations, and those who act as Radiation Protection Advisers for the radiation employers involved. Legislative requirements are first discussed and responsibilities are defined. Guidance is provided on situations when a critical examination is required, what the examination should consider and what constitutes a suitable report. Examples of common situations are discussed.