question: Animal welfare during and as a result of transport can be assessed by using a range of behavioural, physiological, pathological and carcass-quality indicators that are described in this paper. Measures of the extent of any disease, injury or mortality resulting from, or exacerbated by, transport are important because health is an important part of welfare. Many of the indicators are measures of stress as they involve long-term adverse effects on the individual. Factors affecting the welfare of animals before, during and after transport which are discussed are: definition of the responsibilities and competence, attitudes to animals and need for training of staff; planning of journeys and methods of payment of staff; laws and retailers' codes; genetics, especially selection for high productivity; rearing conditions and experience; the mixing of animals from different social groups; handling and loading procedures; driving methods; space allowance; increased susceptibility to disease and efforts to minimise the spread of disease.