Voriconazole is the treatment of choice for invasive aspergillosis and its use is increasing in pediatrics. Minimal pharmacokinetic data exist in young children. We report voriconazole concentrations for 10 children <3 years of age and pharmacokinetic parameters for 1 infant who had therapeutic drug monitoring performed. Trough concentrations were unpredictable based on dose, highlighting the need to follow values during therapy.