Primary ciliary dyskinesia is a rare genetic disease. Early diagnosis is aimed at delaying pulmonary complications, such as bronchiectasis, reducing lung dysfunction and hearing impairment, as well as providing optimal treatment of rhinitis and sinusitis. The awareness of the disease is still poor, and primary ciliary dyskinesia is often underdiagnosed or confused with other diseases, such as asthma. Chronic productive cough and rhinitis, which are the main symptoms, develop already in infancy. Therefore, differential diagnosis is a key element of the diagnostic and therapeutic process. The area of search depends on patient’s age, the nature of symptoms (type of cough, time of symptom onset, repeatability of symptoms), concomitant symptoms and family history. We present a case report of a 4.5-year-old girl with recurrent lower respiratory tract infections and chronic cough, monitored for asthma and unsuccessfully treated with antiasthmatics.