This Technical Specification provides guidance for the requirements in ISO 11135-1:2007. It does not repeat the requirements and is not intended to be used in isolation. The exclusions in ISO 11135-1 apply also to this Technical Specification. For ease of reference, the clause numbering in this Technical Specification corresponds to that in ISO 11135-1:2007. Further guidance for the requirements given in ISO 11135-1 is also included in Annex C of ISO 11135-1:2007 and should be used in conjunction with this Technical Specification. This guidance document is intended for people who have a basic knowledge of the principles of EO sterilization but may need help in determining how to best meet the requirements contained in ISO 11135-1. This document is not intended for people lacking a basic knowledge of the principles of EO sterilization.