Premature ventricular contractions are a rare side effect of filgrastim, reported mainly in elderly men. Here we report the case of a 9-year-old child with thalassaemia who developed frequent premature ventricular contractions after three doses of filgrastim were given for deferiprone-induced agranulocytosis. The arrhythmia resolved 3 weeks after discontinuation of filgrastim. Children treated with filgrastim should be carefully monitored for potentially serious arrhythmia.