OBJECTIVES: To identify the impact of delivery device of inhaled corticosteroids and long-acting β2-agonist (ICS/LABA) on asthma medication compliance, and investigate other factors associated with poor compliance. METHODS: We conducted a retrospective and multicentre study based on a review of medical registries of asthmatic patients treated with ICS/LABA combinations (n=2,213) whose medical devices were either dry powder inhalers (DPI) or pressurized metered-dose inhalers (pMDI). Medication compliance included persistence outcomes through 18 months and medication possession ratios. Data on potential confounders of treatment compliance such as asthma exacerbations, comorbidities, demographic characteristics and healthcare resource utilization were also explored.   RESULTS: The probability of asthma medication compliance in case of DPI was lower compared to pMDI, which suggest that inhaler devices condition inhalation therapies. There were additional confounding factors that were considered as explanatory variables of compliance. A worse measure of airflow obstruction (FEV1), comorbidities and visiting the GP more than once per month decreased the probability of compliance. Within comorbidities, alcoholism was positively associated with compliance. Patients of 29-39, 40-50 and 51-61 age groups or suffering from more than 2 exacerbations during the study period were more likely to comply with their medication regime. We identified differences among DPI devices and Accuhaler^® device impacted negatively greater on compliance compared to other DPIs. We found that GP consultations reduced the probability of medication compliance for patients treated with Formoterol/Budesonide combination. For retired patients, visiting the GP increased the probability of medication compliance. CONCLUSIONS: We concluded that inhaler devices influence patients’ compliance for long-term asthma medication. The impact of DPI on medication compliance was negative. We also identified some confounders of medication compliance such as patient’s age, severity of asthma, comorbidities and healthcare costs.