A presumptive diagnosis of infectious diseases of livestock is based on the case history, clinical examination of ailing animals and postmortem examination of dead animals. But, a confirmatory diagnosis is mainly relay upon laboratory investigation of clinical materials and specimens which are collected from diseased and dead animals respectively. Appropriate samples should be collected aseptically from apparently healthy, clinically affected and dead animals or the environment for a various purpose, such as disease surveillance, disease investigation, herd/flock health certification and monitoring the response to treatment and vaccination. Collected samples should be carefully packaged, labelled and shipped to the diagnostic laboratory by the fastest and reliable method. This book would be highly useful to the Veterinarians who are involved in the collection, preservation, labelling, packaging and shipment of materials for diagnosis of infectious of livestock and poultry.