Previous studies have demonstrated the high incidence of Dermatophagoides, Euroglyphus, Blomia, Lepidoglyphus and Chortoglyphus spp. sensitizations in a mite-allergic population. The aim of this study was to evaluate immunological cross-reactivity among the above mentioned groups, using sera from a nonrural population allergic to mites, from a subtropical area (Canary Islands). RAST inhibition studies demonstrated significant cross-reactivity among Dermatophagoides and Euroglyphus species (> or = 65% of maximum theoretical inhibition), as also noted by other authors. Blomia kulagini demonstrated scarce cross-reactivity with Dermatophagoides, Lepidoglyphus and Chortoglyphus species (< or = 30% of maximum theoretical inhibition) and medium level with Euroglyphus maynei (45% of maximum theoretical inhibition). Chortoglyphus arquatus demonstrated high cross-reactivity levels with the other species studied. The results obtained in this study demonstrated the scarce immunological cross-reactivity between Pyroglyphidae and non-Pyroglyphidae mites, thus suggesting the polysensitization of the studied population to different mite species.