Corpus Christi, TX, is a Gulf Coast city with high humidity levels year-round. There is little available data on mite species in mattress dust, allergen levels, and sensitization to different mite species in allergic patients. This study was designed to determine skin sensitization and specific serum IgE to Dermatophagoides spp. and Blomia tropicalis in patients attending an allergy clinic and to explore the mite fauna and allergen content of their mattresses. Skin-prick tests to Dermatophagoides spp. and B. tropicalis along with mite-specific IgE in the serum by enzyme-linked immunosorbent assay (ELISA) and ImmunoCAP tests were performed in allergic patients attending an outpatient allergy clinic in Corpus Christi, TX. Mite species and allergen levels were determined in mattress dust. Forty-five consecutive patients were evaluated; 10 patients had positive skin tests to Dermatophagoides pteronyssinus and B. tropicalis, 32 patients reacted only to D. pteronyssinus, and 3 patients reacted exclusively to B. tropicalis. Increased titers of D. pteronyssinus- and D. farinae-specific IgE were present and B. tropicalis-specific IgE titers were lower. Significant amounts of mites were observed in 79.5% of dust samples, with a predominance of D. pteronyssinus and D. farinae. Other mite species, such as B. tropicalis, Euroglyphus maynei, Tarsonemus spp., Tyrophagus putrescientiae, Cheyletus spp., and Oribatidae were also observed. Greater levels of Der p and Der f 1 than of Blo t 5 were present in the mattresses. D. pteronyssinus and D. farinae are the prevalent mite species in houses of allergic patients from Corpus Christi, TX. Other mite species are also found.