Children with suspected type 1 diabetes mellitus (T1DM) should have same day referral to a paediatric diabetes team. 99 children (54 male; median age 10.5 years, range 0.9-15.9 years) were diagnosed with T1DM at our hospital between January 2004 and June 2007. 27 (27.2%) presented in diabetic ketoacidosis (DKA). 37 (37.3%) required hospital admission, while the rest had ambulatory management. In 21 (21.2%) children, diagnosis was delayed >24 h (median 3.0 days, range 1-14 days) due to missed diagnosis at the local hospital (four) or by the general practitioner (seven), arranging a fasting blood glucose test (nine) and outpatient appointment requested via fax (one). Children with delayed diagnosis presented more frequently in DKA (52.3% vs 20.5%, p<0.01), with a higher median presenting HbA1c (12.3% vs 10.9%, p<0.05). There were no differences in age and sex between the delayed diagnosis and immediate referral groups. Healthcare providers need to be aware of the importance of immediate referral of children newly diagnosed with T1DM.