BACKGROUND Improper Metered Dose Inhaler (MDI)-spacer use technique can result in less than optimal delivery of medicine to the lungs and poor asthma outcomes. The aim of this study was to evaluate the influence of standardized education on proper MDI- spacer use and asthma control in children with asthma and to identify the factors associated with these results. METHODS This is a cohort study that evaluated the influence of standardized education about MDI-Spacer device use on asthma control in children. Asthmatic children using MDI-Spacer device and their parents were enrolled in this study. Children were followed up for two months after standardized education and the change in asthma control was recorded. RESULTS Thirty eight children (14 females and 24 males) aged between 2.5 and 13 years were enrolled in the study. Mean age of the children was 7.5 ± 2.8 years. Six patients were lost to follow up and thirty two patients completed the study. Mean inhalation technique score was 4.9 ± 1.3 before education and increased significantly to 7.8 ± 0.4 after education (p< 0.001). Mean Asthma Control Questionnaire (ACQ) score decreased significantly with education (0.77 ± 0.9 vs 0.1 ± 0.1 respectively, p< 0.001). Similarly, mean asthma symptom score (ASS) decreased significantly from 4.3 ± 3.6 to 0.2 ± 0.7 with education (p< 0.001). Most common mistake in use of MDI-Spacer device use was detected to be lack of mouth rinsing after use before education in 78.9% of the patients. CONCLUSIONS Providing standardized education about MDI-Spacer device use to children and parents leads to correct MDI-Spacer device use and is associated with improvement in asthma symptom score and asthma control.