Little attention has been given to the patterns of diseases in children admitted to a hospital. We retrospectively studied 874 children (477 male, 397 female) who were hospitalised consecutively during a ten months period to determine the incidence and types of their illness with an emphasis on patterns and causes of fever.Respiratory symptoms of cough and wheezing were the single most common presenting cause of admission (20.3%). Fever (defined as one temperature record of >38.0°C or two successive record of 37.8°C) was the second most common presenting cause (15.8%) leading to admission, and within this group fever without focus was most common. Overall, fever was recorded in 35.9% of the study group. Urinary tract infection was the most common bacterial infection. Children with bacterial infections were usually febrile while the majority of those with presumed viral infections were afebrile. The mean body temperature in children with bacterial infections was significantly higher than in those with presumed viral infections. Overall, febrile children stayed significantly longer in hospital and underwent more laboratory tests compared with afebrile children. Although white blood count and C-reactive protein tended to be higher in bacterial than in presumed viral infections, both tests were sometimes normal in serious bacterial infections and abnormally high in presumed viral diseases. Mild hyponatraemia (<135 mmol/L) was a common laboratory finding in febrile illness, and severe hyponatraemia (<130 mmol/L), was more common in bacterial diseases.It is concluded that febrile illnesses are common and only second to respiratory diseases as the leading cause of hospitalisation. Children with bacterial infection are usually febrile and those with high fever should be evaluated for serious bacterial diseases. Those children who present with fever without focus should be evaluated for an underlying urinary tract infection and bacteraemia.