This paper reviews legal aspects of the collection of fisheries data, particularly in relation to the criteria used to assign responsibilities in relation to the collection and reporting of fishery data and for recording catch data by country. The matter is of concern as a lack of accepted criteria can lead to non-reporting or double reporting of fishery data. This paper reviews the provisions of the principal international fisheries instruments concerning the collection and exchange o f fisheries data. It describes the development of criteria by the Coordinating Working Party on Fishery Statistics (CWP) in the late 1970s and some of their shortcomings. It concludes with presenting refined criteria which were adopted by the CWP in 1999.