BACKGROUND: Tyrophagus putrescentiae is one of the storage mites found not only within storehouses but also in the house dust, and is known as the third most common mite following Dermatophagoides pteronyssinus and Dermatophagoides farinae in houses in Korea. There has been few reports on its sensitization rate in this country. OBJECT: The aim of this study was to evaluate its sensitization rate and clinical features of T. putrescentiae sensitized patients with allergic diseases in Daejeon area. METHODS: Skin prick tests with 33 common inhalant allergens including Tetranychus urticae and T. putrescentiae were done in 308 allergy patients who had visited Allergy Clinic of Eulji University Hospital from June, 2001 to April, 2002, and their clinical characteristics of these patients were analyzed. RESULTS: A total of 193(62.7%) out of 308 patients showed positive responses to more than one allergen. The prevalence of sensitization was highest for mites(51.9%) followed by cockroach (25.0%), weeds pollens(17.5%), animal epithelium(16.9%), fungi(16.2%), grasses pollens(15.6%) and tree pollens(14.6%). Among mites, sensitization rate to T. urticae was highest as 128 (41.6%), followed by D. farinae, 96(31.2%), T. putrescentiae, 95(30.8%), and D. pteronyssinus, 92(29.9%). Among positive responders to mites, eight patients with perennial asthma were sensitized to T. putrescentiae only. Sensitization to D. farinae and animal epithelium were more prevalent in Deajeon city compared to surrounding rural areas (for D. farinae, 72/203(35.5%) vs. 24/105(22.9%) respectively. P=.024, and for animal epithelium, 42/203(20.7%) vs. 10/105 (9.5%) respectively. P=.013). CONCLUSION: Tyrophagus putrescentiae was one of the most common inhalant allergens as well as house dust mite and two spotted spider mite in patients visiting an Allergy Clinic in Daejeon area. Further study will be needed to elucidate the clinical significance of T. putres-centiae -sensitized patients.