Subdural empyema related to Streptococcus constellatus is extremely rare in an immunocompetent child, and also there is no reported case along with Staphylococcus lugdunensis infection. Although Streptococcus constellatus has been determined as a co-pathogen with anerobic bacteria in many infections, it has not been reported in combination with Staphylococcus lugdunensis. The authors describe a case of previously healthy 16-y-old child with unilateral subdural empyema due to these bacteria. Sinusitis was the only predisposing factor in the index case. The authors propose that some cases of culture-negative intracranial infections may be due to these infectious agents. Therefore, these agents should be considered as causes of intracranial infection in persistent complaints such as fever and headache after sinusitis in children. It is important to treat them with effective antibiotics and early surgical intervention for favorable outcome, because fatal cases were reported due to Streptococcus constellatus infections.