Our aim was to study determinants of adherence in young asthmatic children over a 3-month period, including the role of parental illness and medication perceptions as determinants of adherence. Consecutive 2-6-yr-old children with asthma, using inhaled corticosteroids (ICS), followed-up at our paediatric asthma clinic (where patients are being extensively trained in self-management, and are followed-up closely) were enrolled. Adherence was measured electronically using a Smartinhaler® and calculated as a percentage of the prescribed dose. We examined the association of adherence to a range of putative determinants, including clinical characteristics and parental perceptions about illness and medication. Median (interquartile range) adherence, measured over 3 months in 93 children, was 92 (76-97)%, and most children had well controlled asthma. 94% of parents expressed the view that giving ICS to their child would protect him/her from becoming worse. Adherence was significantly associated with asthma control and with parental perceptions about medication. The high adherence rate observed in our study was associated with parental perceptions about ICS need. The high perceived need of ICS may probably be ascribed to the organisation of asthma care (with repeated tailored education and close follow-up).