This manual is the product of countries’ requests for assistance in strengthening and developing national regulatory frameworks related to marine Invasive Alien Species (IAS) in particular with respect to the transfer of potentially harmful aquatic organisms and pathogens in ships’ ballast water and sediments. It is directed at national level practitioners as a hands-on guide to the development of national ballast water management strategies. It is intended as a source of basic information and as step-by-step guidance in the development of national ballast water management strategies.