Abstract Allergy is one of the most widespread diseases of the modern world. More than 25% of the population in industrialized countries suffers from allergies. Allergies, also known as hypersensitive reactions, occur when the immune system overreacts to substances that do not affect most people. These substances, also known as allergens, could be pollen, animal dander, chemicals, fungi, house dust mites, or foods such as nuts, eggs, shellfish, and milk. Different people show different symptoms of allergies, which can be mild (runny nose) to severe (anaphylaxis). Allergen diagnosis of allergic diseases are closely related, in which when a standardized allergen is available, it gives a good chance for proper diagnosis of that allergen-induced disease. Standardization of allergen has been known to imply uniformity of an allergen composition and\or potency that is\are essential not only for diagnosis, but also for immunotherapy. There are several methods for the allergen detection , and most of them are used in diagnosis of allergic diseases , one of them is Skin prick test. Skin prick test (SPT) is a useful way of establishing what allergens a person is sensitized to, but it is important to use allergens relevant to the persons environment as the sensitization pattern may differ across regions. Saudi local extracts are not available in the market so imported extracts are being sold, which cost a lot of money , times and effort. In addition the strains of allergenic substances may not be the same as the local allergens. The objectives of this study were to detect hypersensitivity among young females in King Abdulaziz University by isolating allergens from Jeddah city (pollen, cockroach, animal dander and food). Also; prepare local allergenic extracts from them then use this extracts in diagnosis of allergy by skin prick test. Then detecting IgE levels in serum. The SPT was done on 355 students attending king Abdulaziz University in Jeddah, It had found that the most common allergen were cockroach American (31.5%), then cat epith (29%) and dog epith (29%). And the prevalence of positive skin prick test were 35%.