Inhaled corticosteroids have become the mainstain in the treatment of asthmatic children and adults. Asthma in infancy and early childhood is a heterogeneous condition, with different disease phenotypes and outcome. However, rationale data justifying the use of inhaled corticosteroids in toddlers and preschool children are now available. We recall the results of controlled trials studying the efficacy of inhaled corticosteroids, their potential side-effects, and their actual indications and modalities of prescription.