Mite allergens are one of the major causes of allergic disease. Those that are airborne are particularly harmful because people exposed to them can inhale them without noticing, which does not often happen when the allergens are contained in dust. This chapter provides an overview of the technologies relevant to airborne allergen monitoring systems, which will be useful in preventing exposure. Immunosensors are powerful devices with the ability to detect allergens with high selectivity and sensitivity due to the high specificity of antibodies to antigens. However, immunosensors are not always suitable for monitoring because antibodies are possibly denatured and lose their functions during sensor surface regeneration. To overcome this problem, we give an example of an immunosensor that relies on a surface acoustic wave device and a pH resistant surface architecture. The SAW immunosensor allows repeated and rapid measurement of a house dust mite allergen, Dermatophagoides farinae group 1 (Der f 1). Together with other useful state-of-the-art technologies for the monitoring system, such as bioaerosol samplers and sensors with promising characteristics, the current advances in mite allergen sensors are summarized.