This document specifies: — the general principles governing the biological evaluation of medical devices within a risk management process; — the general categorization of medical devices based on the nature and duration of their contact with the body; — the evaluation of existing relevant data from all sources; — the identification of gaps in the available data set on the basis of a risk analysis; — the identification of additional data sets necessary to analyse the biological safety of the medical device; — the assessment of the biological safety of the medical device. This document applies to evaluation of materials and medical devices that are expected to have direct or indirect contact with: — the patient´s body during intended use; — the user´s body, if the medical device is intended for protection (e.g., surgical gloves, masks and others). This document is applicable to biological evaluation of all types of medical devices including active, non-active, implantable and non-implantable medical devices. This document also gives guidelines for the assessment of biological hazards arising from: — risks, such as changes to the medical device over time, as a part of the overall biological safety assessment; — breakage of a medical device or medical device component which exposes body tissue to new or novel materials. Other parts of ISO 10993 cover specific aspects of biological assessments and related tests. Device-specific or product standards address mechanical testing. This document excludes hazards related to bacteria, moulds, yeasts, viruses, transmissible spongiform encephalopathy (TSE) agents and other pathogens.