© 2017 Elsevier HS Journals, Inc. Purpose Rates of nonadherence to asthma treatment in Spain are between 24% and 76%, which results in poor disease control and increased health care costs. The main objective of this multidisciplinary consensus was to investigate the opinions of health professionals and patients regarding adherence to inhaled therapy in Spain. The results will help to identify the causes of nonadherence and to establish strategies to detect and correct the problem. Methods This research was conducted by using a modified Delphi method organized into 2 rounds and involving a panel of 64 physicians, 16 nurses, and 10 community pharmacists. In addition, 70 patients with asthma completed a simplified 1-round survey, based on the Delphi questionnaire. The items proposed to reach a consensus included topics such as impact and causes of nonadherence, as well as strategies to improve adherence to treatment. Findings Expert panelists reached a consensus on ~80% of the items proposed. They agreed that the lack of control in asthma has an important economic impact. The causes of nonadherence with more agreement were the patients’ beliefs about treatment and the complexity of the inhalation devices. Panelists agreed that the most important strategies to improve adherence were modification of patients’ beliefs, training of professionals in the management of adherence, and personalization of interventions. Most patients only agreed with items that referred to strategies to improve adherence. Implications Although the problems, impact, causes, and interventions regarding nonadherence to asthma treatment are known, adequate monitoring of adherence to treatment is not performed. A multidisciplinary and personalized approach is necessary to control and improve adherence.