House dust mites are the most common sources of allergic sensitization, primarily responsible for the occurrence of various clinical forms of respiratory and skin allergies, but also of certain forms of food allergy. There are many various mite species, of which only a small number are constantly or occasionally found in house dust samples. Mites from Pyroglyphidae family, Dermatophagoides pteronyssinus and Dermatophagoides farinae are most frequently responsible for sensitization of susceptible persons. Other less commonly found species may represent individual primary sources of sensitization, or may cause disease symptoms due to cross-reactivity. The exposure to various mite species within different geographical regions accounts for the generation of various sensitization profiles. Knowing these profiles is important for planning rational specific immunotherapy, which greatly determines its efficacy. The aims of this paper are to review the environment conditions that influence mite incidence and the ways their changes can control allergen amounts in patient homes, to review the allergenic content and the significance of cross-reactivity among mite allergens, and finally, to explain the factors that enable the generation of various sensitization profiles.