Preference measurement is an important concept in health economics. The theory provides a common outcome measure that can be compared across diseases. Instruments used to measure preference, such as the standard gamble, time trade-off, visual analog scale and multiattribute health state classification systems, have been used in asthma studies. However, preference measurement has not been routine in asthma studies, partially because of concerns about the sensitivity of the instruments in detecting important changes in asthma. The development of disease-specific, preference-based instruments may change that trend. However, such instruments move away from the goal of providing a single summary measure comparable across diseases. The instruments used to measure preference and preference results in asthma studies are reviewed in this paper.