Objectives. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been recognized as the first method of choice in the diagnosis of mediastinal and hilar lesions. Although the procedure is commonly used, there is no study assessing its contribution to the duration required for diagnosis and treatment. In this study, we aimed to determine the extent of diagnosis and treatment delays when using the EBUS-TBNA procedure and to address the possible factors contributing to these delays. Materials and Methods. The demographic data, pathological diagnosis, need for additional procedures, symptoms, presenting complaints, and the time until the beginning of treatment were recorded retrospectively in all patients who had undergone EBUS-TBNA. Results. A total of 134 patients (mean age 60.7 ± 12 years, M/F: 78/56) were included. Delay of the patients was found in 60.4% (n = 81), delayed referral in 35.8% (n = 48), diagnosis delays in 84.3% (n = 113), treatment delays in 38.8% (n = 52), and total delay in 73.1% (n = 98) of the patients. A statistically significant association was found between referral delay and total delay with age groups (
p
=
0.006
) and between patient delay and the presence of symptoms (
p
=
0.027
). EBUS-TBNA was found to have the lowest effect among all delay parameters (β: 0.104,
p
<
0.001
) in the regression analysis. When diagnosis times’ subgroups were compared, EBUS-TBNA was found to have the least effect (correlation coefficient: 0.134,
p
=
0.004
). Conclusion. We found that approximately ¾ of the patients had a delay and this is not acceptable in real terms. Considering that the patient burden is increasing day by day, it is necessary to make a radical change in health care or a change in strategy in order to prevent delays. EBUS-TBNA, which is in the diagnosis delay subgroup, is less invasive and accelerates the process.