Invasive fungal infections are important causes for treatment-related morbidity and mortality in severely immunocompromised paediatric patients with haematological malignancies or in children undergoing haematopoietic stem cell transplantation. In addition, neonates, in particular preterm infants, are at risk for invasive mycoses. The past decade witnessed a major expansion of antifungal drug research, which has resulted in the development of new antifungal agents. Caspofungin is the first licensed compound of the novel class of echinocandin lipopeptides. Although the compound is not yet licensed in the paediatric population, caspofungin is increasingly prescribed in children. This article reviews the clinical pharmacology of caspofungin and the published experience with the drug in neonates and immunocompromised children.