OBJECTIVE Poor inhalation technique may impact both asthma control and compliance in patients with asthma. The SYSTER survey is therefore aimed at assessing the influence of starting or switching an existing therapy to a breath-actuated pressurized metered dose inhaler (pMDI, Autohaler) on these parameters. METHODS 709 French general practitioners (GP) enrolled 2588 asthmatic patients in whom therapy with the breath-actuated pMDI was either initiated, or a switch from an existing inhalation device to the said inhaler was deemed necessary. Asthma control was assessed at inclusion and after 4 weeks of treatment with the Juniper Asthma Control Questionnaire (ACQ). In addition, patient adherence was estimated according to the self-reported Morisky scale. RESULTS 1510 patients (mean age 39 years, standard deviation 18 years; 53% male) completed follow-up after 4 weeks. The main reasons for inhaler change were poor asthma control (49%) and poor coordination (40%). After 4 weeks of therapy with the breath-actuated pMDI, asthma control significantly improved from 2.35 +/- 1.05 to 1.32 +/- 0.93 in the ACQ (p < 0.0001). Also, self-reported patient adherence improved from 2.11 +/- 1.43 to 1.57 +/- 1.53 on the Morisky scale (p < 0.0001). CONCLUSIONS These results suggest that by focusing on the inhalation devices, asthma control and compliance with treatment are improved.