BACKGROUND: Asthma is a chronic condition with a high health and social burden in children. Although many well-studied effective therapies are available, because of suboptimal adherence and inhalation technique, asthma in children remains frequently uncontrolled. It is often assumed that adherence and technique are highly correlated items, but this assumption has not been thoroughly validated. OBJECTIVE: This trial evaluates the correlation between adherence and inhalation technique and the association of patient-related factors with these two important parameters. DESIGN: Observational phase I of the IMproving Adherence by Guiding INhalation via Electronic monitoring (IMAGINE) study, a three-phased Randomized Controlled Trial (RCT) in children with uncontrolled asthma. METHODS: The observational phase I of the IMAGINE study was designed to determine the correlation between adherence and inhalation technique in pediatric subjects with uncontrolled asthma. During this observational study phase, adherence and inhalation technique were measured with a smart add-on device called Respiro (Amiko, London). Patient-related factors were assessed either at baseline (e.g. characteristics of the patient), or during the study period (e.g. number of emergency room (ER) visits and daily salbutamol intake). RESULTS: Of the 34 enrolled subjects, 6-18 years old, suffering from moderate to severe uncontrolled asthma, 32 successfully completed phase I. No significant correlation between adherence and inhalation technique was observed ( = -0.21;  = 0.234). Twenty-one percent of children had both good adherence and good inhalation technique. Children with good adherence had more often ⩾1 ER visits during follow-up, while poor inhalation technique was associated with younger age and lower height at baseline, and a higher daily salbutamol dosage intake and ⩾1 ER admission during follow-up. CONCLUSION: Our findings demonstrated no correlation between therapy adherence and inhalation technique, suggesting that these should be regarded as distinct and frequent pitfalls of inhaled medication use.We observed that inhalation technique was significantly associated with ER visits, rescue medication use, age, and height, while good adherence correlated with ER visits. Recognizing these factors allows pediatricians to identify risk profiles for poor inhalation technique and poor adherence, enabling more targeted and personalized interventions. NL-OMON25807.