In New Zealand, blood is harvested from horses, cattle, sheep and goats for research (eg preparation of specific antisera) and commercial purposes (eg vaccine production). Due to the country's favourable disease status there is a growing demand from other countries for harvested blood and it is expected that the blood-harvesting industry in New Zealand will grow. These guidelines were drawn up for use by local Animal Ethics Committees in New Zealand in order to safeguard the welfare of animals used for blood-harvesting. The guidelines contain sections on facilities and equipment, bleeding techniques, volume and frequency of bleeding, animal monitoring (including monitoring of packed cell volume) and other aspects of blood-harvesting. It is stated that not more than 15 per cent of estimated circulating blood volume should be removed in any four week period. However, it may be acceptable in some circumstances, with the approval of the institutional Animal Ethics Committee, for up to 25 per cent of estimated circulating blood volume to be removed. The document is required reading for people involved with the blood-harvesting industry in New Zealand but it is also likely to be of interest and value to those involved in similar work elsewhere in the world.