This study describes the Quebec system of compensation for occupational asthma, assessing the functional and social outcome of claimants and estimating the efficiency and cost. Information was obtained on the clinical, functional and social outcome as well as the estimated costs for 134/211 subjects (participation rate of 64%), who received compensation between 1986 and 1988. At the time of assessment (2 years and more after the diagnosis), 93% of participants still demonstrated significant bronchial hyperresponsiveness and 84% required anti-asthma medication. None of the participants remained exposed to the offending agent: 67% were working for the same or another employer, 16% were retired, 8% were retraining for a new job and 8% were still unemployed. Quality of life was mildly affected, more so than for a control group of subjects. The mean interval between the time claims were addressed and the first medicolegal decision was 8.1 months. The mean total cost (including temporary and permanent disability indemnities, medical and technical costs) was $CAN 49,200 (minimum and maximum values of $2,100 and $330,900). We conclude that for subjects with occupational asthma in Quebec: 1) the mean interval for a medicolegal decision to be made is eight months: 2) a minority is still unemployed two to four years after being assessed; 3) the quality of life is more affected than in a control group; 4) the mean cost is close to $CAN 50,000.