The Sickness Impact Profile is a quality of life scale developed in the United States which is now widely used in clinical trials in chronic conditions such as chronic obstructive lung disease, angina, rheumatoid arthritis, chronic pain, psoriasis, inflammatory bowel disease and cancer. Validated generic scales permit cross cultural comparisons within disease processes in clinical trials. As a simple, direct translation of a scale is inadequate, we have created a French version of the original US version of the Sickness Impact Profile. The first phase was qualitative. A first French translation of the original US version was back translated into English by three independent translators. A second French version resulted from a consensus reached by a panel of lay subjects and health professionals after comparing the original US version, the first French version and the three back translations. This second version was tested with a group of 40 healthy volunteers. This qualitative phase resulted in a French Test Version with content and face validity. The quantitative phase assessed the equivalence of the rank order of each item, by sub scale, in the US version with that of the French Test Version, ie the rank of the French item was comparable (+/- 2) to the rank of the corresponding US item. The French Test Version was tested with 47 healthy subjects. Of the 136 items of the Sickness Impact Profile, 13 were retranslated to create a final French version. This was similarly tested on ten healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)