This part document describes: – the general principles governing the biological evaluation of medical devices within a risk management process; – the general categorization of 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 part document applies to evaluation of materials and devices that are expected to have direct or indirect contact with the patient’s body during intended use. In addition, this document applies to medical devices that are expected to have direct or indirect contact with the clinician’s body, if the device is intended to protect the clinician (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. Biological hazards arising from other risks, such as mechanical failures or changes to the device over time, should be considered as a part of the overall biological safety assessment, and can be addressed by relevant biocompatibility, mechanical or other in vivo animal testing or other information. Other parts of ISO 10993 cover specific aspects of biological assessments and related tests.