This article reports on a 5-month long prospective survey carried out in 1990 on 208 patients aged 18 and over, suffering from moderate to severe asthma. The recorded data included information on the history of the illness, the respiratory problems encountered and asthma attacks, the repercussions the illness had on household and professional occupations, the perceived state of health, drug consumption and recourse to external services. The medical costs and production loss due to this pathology were also estimated.