The Formoterol and Corticosteroids Establishing Therapy (FACET) study has provided the first opportunity to examine the long-term effects of inhaled steroids and long-acting beta2-agonists on asthma-specific quality of life. The objectives of the present study were to: evaluate the effects of long-term (1 yr) formoterol and increasing doses of budesonide on asthma quality of life; 2) to determine whether initial improvements in quality of life are sustained when improvements in clinical indices persist; and 3) to evaluate the long-term relationship between changes in clinical indices and changes in quality of life. Of the 852 asthmatic adults enrolled, 470 from five countries participated in this quality of life evaluation. After a 4-week run-in on 1,600 microg budesonide, patients were randomized to either 200 microg (Bud200) or 800 microg budesonide (Bud800) in combination with either 24 microg formoterol (F) or placebo daily for 1 yr. The Asthma Quality of Life Questionnaire (AQLQ) was completed and conventional clinical indices measured at enrolment and randomization and on seven occasions during the following 12 months. During the run-in, there was an improvement in AQLQ score (changes (delta) in overall score approximately 0.50; p<0.0001). After randomization, there was a further improvement in the Bud800+F group (delta=0.21; p=0.028). One month post-randomization, improvements in all groups stabilized and were sustained throughout the 12 months in a pattern very similar to that observed for the conventional clinical indices. The correlation of individual patient changes in clinical indices and changes in AQLQ score during the 12-month randomized period were weak to moderate (maximum r=0.51). Improvements in quality of life, which were greatest in the 800 microg budesonide plus 24 microg formoterol group, were sustained throughout the 12 months in a similar manner to the clinical indices. Long-term changes in conventional clinical indices cannot be used to predict the effect of treatment on individual patient experience.