Fever is a symptom who is often the reason why parents bring their children to the doctor, fever is defined as oral ≥ 37.8°C. Axillary temperature ≥ 37.2°C. or rectal temperature ≥ 38°C. in children under 5 years of age. Children with fever may or may not have signs or symptoms associated with the lesion or cause. Four conditions require special attention: the severity of the disease cannot be predicted in infants younger than 2 months of age with fever. A severe infection has a mild and nonspecific clinical presentation. Therefore, all infants younger than 2 months of age with fever (e.g., rectal temperature >38°C) should be thoroughly examined by a physician, including blood cultures, urinalysis, and lumbar puncture. In addition to this, antibiotic treatment should be started while waiting for the results of the laboratory tests. Children 6-24 months old When the body temperature is greater than 38.9°C. and a wbc less than 5 *109 or more than 15 *109 there is a risk of bacteremia. Blood cultures, lumbar puncture, urinalysis, and chest x-ray should be considered to determine the cause. Children with impaired immune function are at risk for G- or G+ sepsis. Children with functional or anatomic absence of spleen are at risk for fulminant infections caused by Streptococcus pneumoniae, Salmonella, etc. Prompt application of antibiotics is required. T>41°C is usually associated with bacterial infections. Bacteraemia and meningitis should be excluded.