An integral part of the operation of a tritium-handling facility is the need to maintain a tritium accounting system which meets both operational and regulatory requirements. The Darlington Tritium Removal Facility processes heavy water to remove tritium for storage or sale. The Chalk River Tritium Laboratory is a general-purpose experimental facility, handling various quantities and specific activities of tritium in separate systems, including re-packaging of tritium from large metal-getter storage beds to smaller aliquots. Tritium accounting procedures, analytical techniques and operational experience gained to date in the operation of these tritium-handling facilities are described.