Objective Patients with primary ciliary dyskinesia (PCD) may present with different clinical findings at different ages, and age at diagnosis may differ. We aimed to review clinical factors that affected age at diagnosis of patients with PCD. Study Design All 70 patients with PCD who were followed in our pediatric pulmonology department were included. Demographic features, clinical findings, PrImary CiliAry DyskinesiA Rule (PICADAR) scores and pulmonary function tests of patients were recorded and clinical factors that affected age at diagnosis were evaluated. Results The mean age at diagnosis was 8.3 +/- 4.6 years. Most of patients (95.7%) had a persistent wet cough. The mean PICADAR score was 6.5 +/- 3.2, and there was a negative correlation between PICADAR and age at diagnosis (r = -0.271, p = .023). The mean ages at diagnosis of patients with situs abnormality and recurrent wheezing were earlier than in patients without situs abnormality and recurrent wheezing (6.7 +/- 4.3 and 6.8 +/- 4.3, p = .002 vs. 9.8 +/- 4.3 and 9.0 +/- 4.6 years, p = .040, respectively). The mean age at diagnosis of patients with bronchiectasis was later than in patients without bronchiectasis (10.8 +/- 3.9 and 6.9 +/- 4.4 years, p = .001). Other clinical features were not statistically significant according to age at diagnosis (p > .05). There was no statistically significant relation between age at diagnosis and sex, sibling or relative with PCD and parental consanguinity (p > .05). Conclusion Although most patients diagnosed with PCD had symptoms, the diagnosis may be delayed. High PICADAR score is a useful guide to evaluate PCD. Situs abnormality and recurrent wheezing could be clues for early diagnosis of PCD. Early diagnosis of PCD may prevent bronchiectasis.