Three cases of sinusitis in children accompanied with intractable fever and general symptoms like meningitis were experienced. Physical examination and clinical courses favored the diagnosis of complications of sinusitis.Case 1. A 10-year-old child was referred to our department because of intractable fever, headache, vomiting, and dysphagia. The symptoms suggestive of meningitis were considered to be caused by otitis media or sinusitis. Intravenous administration of panipenem/betamipron (PAPM/BP) relieved the symptoms.Case 2. A 9-year-old child was hospitalized because of intractable fever accompanied with postnasal drip and dysphagia. Intravenous administration of clindamycin relieved the symptoms. The symptom similar to that of meningitis was ascribed to sinusitis.The preceding therapy with antibiotics made it difficult to determine the causative pathogens in the two cases.Case 3. A 2-year-old child was hospitalized due to intractable fever accompanied by toothache and swelling of the left cheek and eyelid. Under the suspicion of acute osteomyelitis of maxilla, the patients was treated with intravenous administration of cefazolin (CEZ), clindamycin, and immunoglobulin, followed by a favorable outcome. The medication relieved the symptoms.With the recent advances of antibiotics, the incidence of osteomyelitis of maxilla has decreased dramatically. But high infection rate of staphylococcus, especially the MRSA, among infants less than two months of age remained to be a clinical problem. Our case was an example of victims of Moraxalla Catarrhalis infection.Since sinusitis of children does not always represent the typical symptoms that appear in the sinusitis of adults, fever resulting from sinusitis might be mistaken for that of unknown origin.Our patients had the symptoms of intractable fever, headache and vomiting--sinusitis. These symptoms should remind us to treat patients taking the existence of sinusitis into consideration for differential diagnosis.