To measure Derp1 and Blot5 allergen levels in asthmatics’ homes in Hongkong. Methods Seventy houses were enrolled for a mite indoor environment study. Dust samples were obtained from two sites of each patients’ house: bed and floor. Derp1 and Blot5 levels were quantified by a two-site monoclonal antibody-based ELISA technique. Results The levels of Derp1 allergens found in bed (geometric mean (GM) 3.43 μg/g of dust; 95%CI, 1.89-4.96 μg/g) and on the floor (GM 1.12 μg/g of dust; 95%CI, 0.71-1.53 μg/g) indicated significant differences (P = 0.005). However, the levels of Blot5 allergens found in bed (GM 19.00 μg/g of dust; 95%CI, 0.89-38.90 μg/g) and on the floor (GM 6.14 μg/g of dust; 95%CI, 0.40-11.90 μg/g) showed no statistically significant difference. In addition, in regards to the exposure index for Derp1 and Blot5 allergens found in bed and on the floor, 17.6% in bed and 8.6% on the floor had levels of Blot5 ≥ 10 μg/g of dust, higher than those obtained for Derp1 (7.2% and 0% in bed and on the floor respectively, P < 0.05); higher percentages in bed and on the floor (25.0% and 35.7%) were observed for levels of Blot5 = 0 μg/g of dust as compared with Derp1 in bed and on the floor (4.3% and 14.5% respectively, P < 0.05). Conclusions Derp1 and Blot5 are the major allergens found in this regional study, Blot5 is a more potent allergen in Hongkong, probably reflecting the high level of exposure to Blomia tropicalis (Bt). Bt and Dermatophagoides pteronyssinus(Dp) allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in Hong-kong. To measure Derp1 and Blot5 allergen levels in asthmatics ’homes in Hongkong. Methods Seventy houses were enrolled for a mite indoor environment study. Dust samples were obtained from two sites of each patients’ house: bed and floor. Derp1 and Blot5 levels were quantified by Results of these two levels of Derp1 allergens found in bed (geometric mean (GM) 3.43 μg / g of dust; 95% CI, 1.89-4.96 μg / g) and on the floor 95% CI, 0.71-1.53 ​​μg / g) indicated significant differences (P = 0.005). However, the levels of Blot 5 allergens found in bed (GM 19.00 μg / g of dust; 95% CI, 0.89-38.90 μg / g) and on the floor (GM 6.14 μg / g of dust; 95% CI, 0.40-11.90 μg / g) showed no statistically significant difference. In addition, in regards to the exposure index for Derp1 and Blot5 allergens found in bed and on the floor, 17.6% in bed and 8.6% on the floor had levels of Blot5 ≥ 10 μg / g of dust, higher than those obtained for percentages in bed and on the floor (25.0% and 35.7%) were observed for levels of Blot5 = 0 μg / g of dust as compared with Derp1 in bed and on the floor (4.3% and 14.5% respectively, P <0.05). Conclusions Derp1 and Blot5 are the major allergens found in this regional study, Blot5 is a more potent allergen in Hongkong, probably reflecting the high level of exposure to Blomia tropicalis (Bt). Bt and Dermatophagoides pteronyssinus (Dp) allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in Hong-kong.