Background/aim: Bordetella pertussis infection remains an important health problem in adults due to the increasing prevalence in recent years. Pertussis in adults can be easily overlooked or misdiagnosed. We aimed to determine the prevalence of pertussis in adult patients with acute cough and the clinical features of the pertussis cases. Materials and methods: Internal Medicine and Pulmonology inpatient wards and outpatient clinics were screened between March 2017 and June 2018. Patients with cough duration between 1 week and 1 month were enrolled. Those who were on antibiotics for more than 5 days were excluded. A total of 115 patients were enrolled. Nasopharyngeal swabs were taken and real-time polymerase chain reaction analyses were done. Results: According to the pertussis case definition, 47.8% of the patients were diagnosed with probable pertussis. We found the prevalence of pertussis as 3.5% in our cohort. All of the patients with pertussis had a history of paroxysmal cough with a mean duration of 20 days. Conclusions: These results show that pertussis continues to be a health problem for adults and may present with acute cough. The growing number of adult pertussis cases suggest that vaccination of children is inadequate to prevent pertussis and the concept of ‘lifelong vaccination’ should be strengthened.