Objective: The AeroChamber Plus (AC) valved holding chamber has been enhanced to include the Flow-Vu (FV) inspiratory flow indicator that provides visual inhalation feedback during use. We have investigated if FV alters asthma control and whether parents accept it. Methods: At visit 1, children with asthma, age 1-5 years, used an AC with their pressurised metered dose inhaler and 2 weeks later (visit 2) they were randomised to use either AC or FV. Subjects returned 6 (visit 3) and 12 (visit 4) weeks later. The Asthma Control (ACQ) and Paediatric Asthma Caregiver's Quality of Life (PACQLQ) questionnaires were scored at each visit, and their peak inhalation flow (PIF) when they used their spacer was measured. Results: Forty participants in each group completed the study. There was no difference in the ACQ scores from visits 2 to 4 between the two groups. The improvements in the PACQLQ scores were greater in the FV group (p=0.029). The mean difference (95% confidence interval) for the change from visits 2 to 4 between FV and AC groups was 0.05 (-0.33, 0.43) and 0.39 (0.035, 0.737) for the ACQ and PACQLQ, respectively. Most parents preferred the FV (p<0.001). There was no difference in the PIF rates at each visit and between the two spacers. Conclusions: There was no change in asthma control of the young children but that of their parents improved. Parents preferred the FV and this could be related to their improved perception of their children's asthma control by better PACQLQ scores.