The Asthma Autonomy Questionnaire (AAQ) was designed to evaluate asthmatics' desire to learn about their disease and to make decisions. The AAQ consists of 26 items distributed in two scales: Preferences in the Search for Information (PSI, 8 items) and Preferences in Decision Making (PDM, 6 general items and 12 related to 3 scenarios depicting asthma in stable phase, during mild exacerbation and during severe exacerbation). The aim of this study was to analyze the internal consistency (Cronbach's-coefficient) and content validity (factorial analysis of principal components) of the AAQ. After translation and back translation, the Spanish version of the AAQ was administered to 115 adult asthmatics of both sexes and differing levels of severity. The alpha coefficients for the two scales and 3 scenarios ranged from 0.42 (PSI) to 0.73 (stable phase scenario); only for the stable-phase scenario were values high or statistically acceptable. Factorial analysis reproduced the content of the scales only approximately, with some items proving to relate to factors that were different from the scale they originally belonged to. These results indicate that, in its current formulation, the AAQ presents important measurement problems and revision is advisable.