The understanding of a written text is directly related to the readability level of that text. Readability can be measured objectively using specific formulas. In this study, we aimed to determine the readability level of the drug package inserts of antidepressant drugs. A total of 51 drug package inserts were grouped according to antidepressant types. Title and drug license information was removed from the texts for standardization. These were evaluated using the Ateşman, Bezirci–Yılmaz and Çetinkaya–Uzun readability formulas, applicable to Turkish texts. The average Ateşman readability score was determined as 71.4. Accordingly, it was seen that the drug package inserts require a grade 7-8 of education for readability. The readability level of the Bezirci-Yılmaz formula was, similarly, of grade 7-8 (primary education) level. The Çetinkaya-Uzun readability score was calculated as 45.4 and an 8-9th grade level was determined. It was ascertained that the drug package inserts were readable at the secondary education (7th-9th grade) level on average. Considering the average education level in Turkey, it was established that the readability level was therefore high. We believe that writing the drug package inserts based on the average education level will increase readability and therefore intelligibility.