INCLUSION CRITERIA 1. Provision of informed consent prior to any study specific procedures. For patients under-age, signed informed consent from both the patient and the patient's parent/legal guardian is required 2. Male or Female, ≥12 years of age 3. Documented diagnosis of asthma for at least 6 months prior to Visit 1 4. Patients who are in need of Step 2 treatment according to Global Initiative for Asthma guidelines 5. Patients treated with 'as needed' inhaled short-acting bronchodilator(s) only should have pre-bronchodilator Forced Expiratory Volume in one second (FEV1) ≥ 60 % of Predicted Normal (PN) and post-bronchodilator FEV1 ≥ 80 % PN 6. Patients treated with low stable dose of inhaled corticosteroid or leukotriene antagonist in addition to 'as needed' use of inhaled short-acting bronchodilator(s) should have pre-bronchodilator FEV1 ≥80 % PN 7. Patients should have reversible airway obstruction 8. To be randomized patients must have used Bricanyl Turbuhaler 'as needed' on at least 3 separate days during the last week of the run in period. EXCLUSION CRITERIA 1. Patient has a history of life-threatening asthma including intubation and intensive care unit admission 2. Patient has had an asthma worsening requiring change in treatment other than inhaled short-acting bronchodilator(s) within 30 days prior to Visit 1 or between Visits 1 and 2; or a treatment other than Bricanyl Turbuhaler from Visit 2 until randomization 3. Patient has required treatment with oral, rectal or parenteral glucocorticosteroids (GCS) within 30 days and/or depot parenteral GCS within 12 weeks prior to Visit 1 4. Smoker (current or previous) with a smoking history of ≥ 10 pack years 5. Pregnancy, breast-feeding or planned pregnancy during the study.