We report the case of a 15-year-old female, with no previous medical history, who presented cardiac tamponade secondary to purulent pericarditis caused by Neisseria meningitidis serogroup C. This microorganism is the etiologic agent in 6-16% of the cases of purulent pericarditis, most in association with previous or concomitant central nervous system involvement (meningitis). Exceptionally, as in this case, the pericarditis is not accompanied by meningitis (Primary Meningococcal Pericarditis). The patient was treated with antibiotics, pericardiocentesis and steroids with excellent response. It is important to point out that meningococcal disease may present in unusual forms which may lead to diagnostic and therapeutics difficulties.