Introduction. We present a case of sepsis caused by isolated sphenoiditis. Material and method. The case being described concerns 61-year-old woman treated at the Department of Occupational Diseases of Wroclaw Medical University due to body temperature maintaining for 2 months at above 38°C, leucocytosis reaching 14–16 thousand and weight loss of about 4 kg. Detailed diagnostics did not confirm the preliminary diagnosis of system or neoplastic disease. Bacteriological blood examination revealed the presence of staphylococcus aureus susceptible to Vancomycin and Tienam. The attempt of pharmacological treatment did not produced the expected effect. NMR examination of the facial skeleton proved partial shadowing of the Sphenoidal sinus. The patient was admitted for surgical treatment. After the sphenoidal sinus was cut open, mucopurulent contents was found inside. During microbiological examination, staphylococcus aureus with identical susceptibility was cultured from the mucopurulent contents. After 3-week gui ed antibiotic therapy, permanent temperature regression and permanent improvement of the patient’s condition were achieved. Results. Surgical treatment combined with intensive antibiotic therapy caused the complete regression of symptoms. Conclusion. Isolated sphenoiditis occurs rarely but it still is a serious diagnostic and therapeutic problem. Diagnosis delay and disease progress may lead to life-threatening complications.