In recent years there has been a worldwide increase in demand for subjective measures of health-related quality of life (HRQL). Researchers have the choice of whether to develop a new measure or whether to adapt an existing measure in another language. This review evaluates the processes used in translating and adapting nine generic HRQL instruments (15D, Dartmouth COOP/WONCA Charts, EuroQol, HUI, NHP, SIP, SF-36, QWB, WHOQOL) for use in Africa, Asia, Eastern Europe, the Middle East, and South America. The review adopts a universalist model of equivalence, outlined by Herdman, Fox-Rushby, and Badia (Qual. Life Res. 7 (1998) 323), to judge the 58 papers reviewed. Research spans 23 countries and is dominated by research in the East Asia and Pacific region and the SF-36. Results are reported for conceptual, item, semantic, operational, measurement and functional equivalence. It is argued that currently there is a misguided pre-occupation with scales rather than the concepts being scaled and too much reliance on unsubstantiated claims of conceptual equivalence. However, researchers using the WHOQOL approach are more likely to establish reliable conclusions concerning the equivalence of their instrument across countries. It is a key conclusion of this review that research practice and translation guidelines still need to change to facilitate more effective and less biased assessments of equivalence of HRQL measures across countries.