Pertussis is an acute contagious human disease caused by gram-negative Coccobacilli Bordetella pertussis. Numerous factors and toxins produced by Bordetella pertussis play important role in pathogenicity of the disease. Typical illness has three clinical stages: catarrhal, paroxysmal and convalescent. In therapy erythromycin is the antibiotic of choice. We present a case of pertussis in a seventeen year old, previously vaccinated patient.