The medicolegal aspects (primary prevention, secondary prevention or surveillance) and the system of compensation (tertiary prevention) for occupational asthma are reviewed in this article. Due to the significant medical, medicolegal, social and financial consequences, it is of the utmost importance that the diagnosis of occupational asthma be proved by objective means, whenever feasible. Compensation for temporary and permanent disability/impairment should be offered to workers. Attempts to retain subjects rapidly and efficiently are preferable, as occupational asthma generally affects young workers. The evaluation of permanent asthma and the awarding of relative permanent disability compensation should be effected 2 yrs after exposure to the causative agent has ended, as asthma generally persists even after exposure to the causative agent ceases. A tabulated review of prevailing medicolegal compensation systems in various countries is presented. Data on an evaluative assessment of the Quebec system of compensation are included.