1428 patients with respiratory conditions (rhinitis, asthma, rhinitis in association with asthma) were studied, 296 patients (20.72%) producing positive skin reaction to moulds either in isolation or in association. Of the 296, 29.95% of subjects with rhinitis, 38.74% of the asthmatics and 31.26% with rhinitis and asthma were sensitive to moulds. The onset of allergic symptoms occurs most frequently in 20-30 year olds. Most patients were permanently affected. The Mucoraceae were the phycomycetes most frequently producing an allergic reaction.