Education on optimal medication use is an essential strategy to improve asthma control. The current authors investigated whether pharmacist interventions, focused on appropriate use of asthma medication and tailor-made to the patient's current asthma control, would improve asthma control in adult patients. A 6-month randomised, controlled, parallel-group trial was conducted in 66 community pharmacies in Belgium. Patients were randomly assigned to receive usual pharmacist care (n = 94) or a pre-defined pharmacist intervention (n = 107). This intervention mainly focused on improving inhalation technique and medication adherence. Primary outcome was the level of asthma control, as assessed by the Asthma Control Test (ACT). Mean ACT scores did not change from baseline for both study groups. However, a pre-defined subgroup analysis of patients having insufficiently controlled asthma at baseline showed that the intervention had significantly increased the ACT score after 6 months compared with usual care. The intervention also reduced, for the complete study group, reliever medication use and the frequency of night-time awakenings due to asthma. Inhalation technique and adherence to controller medication were significantly better in the intervention group. In conclusion, pragmatic community pharmacy-based programmes can significantly improve therapeutic outcomes in adult asthma patients.