This retrospective case series describes the clinical spectrum of 43 children with pandemic (H1N1) 2009 admitted to a single hospital in Australia during the peak winter flu season. Clinical features, diagnoses, length of hospitalisation and complications were reviewed in children up to 17 years of age with proven pandemic (H1N1) 2009 by RT-PCR. The median age was 6 years, 42% had a pre-existing medical condition. The most common presentation was fever and cough, and 88% of patients met our criteria for flu-like illness. Consolidation on chest x ray was the most common diagnosis (n=20, 46%), followed by dehydration (n=13, 30%). Three (7%) had encephalopathy and two (5%) had diabetic ketoacidosis. There were two intensive care admissions and no deaths. Pandemic (H1N1) 2009 flu has a wide range of presentation in the paediatric population. The diagnosis should be considered during the current pandemic in any child with fever, or who is unwell.