The blood cold chain is a series of interconnected activities involving equipment, personnel and processes that are critical for the safe storage and transportation of blood from collection to transfusion. Breaks in the cold chain happen for many reasons, such as equipment that does not meet standards of quality and safety, is unsuitable for blood storage, or is not properly maintained or repaired. The major items of blood cold chain equipment are refrigerators, freezers and transport boxes. Temperature monitors are essential during storage and transportation, and alarms are fitted to storage equipment to alert users should the temperature deviate from the acceptable range. There are many other cold chain devices and accessories such as standby generators and voltage regulators. The World Health Organization (WHO) promotes the adoption in countries of a comprehensive life cycle approach to blood cold chain equipment that comprises: planning and decision-making, acquisition, installation; preventive maintenance, care and repair; monitoring of performance and use, and decommissioning. Selection and acquisition of blood cold chain equipment were covered extensively in the publication The Blood Cold Chain: Guide to the Selection and Procurement of Equipment and Accessories. In that Guide, WHO provided blood bank managers, procurement agencies and manufacturers with a description of, and minimum performance specifications for all the essential equipment needed for the efficient storage and transportation of blood and blood components. This new, complementary publication concentrates on the later stages of the life span. Detailed explanations, illustrations and standard operating procedures provide all users of blood cold chain equipment with information on how to receive, install, operate, maintain and monitor the equipment. Preventive maintenance and rational use prolongs the life of the equipment, significantly decreases safety risks and reduces replacement costs. Activities and exercises are offered to make the information as relevant as possible for the reader. Blood cold chain managers are encouraged to adapt the information in this manual to personalize training materials for their staff. The manual may also serve colleges that train technical staff who will work in blood banks, and act as a resource to familiarize refrigeration engineers with the special requirements for blood cold chain in a hospital setting. The ultimate objective of the WHO Blood Cold Chain Project is to increase the availability and provision of safe blood to all populations.