β-Thalassemia (β-thal) is a frequent, chronic hereditary disease, and a plausible cause for psychological disorders. In this cross-sectional study, we aimed to identify the rate and severity of depression among Iranian patients with β-thal using the Beck's Depression Inventory (BDI). β-Thalassemic patients aged 13-20 years [median age 17.2 years; 27 males (48.2%), 29 females (51.8%)], who presented to the Mofid Children Hospital, Tehran, Iran, for blood transfusions within a 1-year period, were asked to complete the BDI questionnaire. Based on the BDI score, patients were classified as normal or mild-to-severe depression groups, and the collected data were then analyzed according to age and sex. A total of 56 subjects completed the BDI form. Mean score for BDI was 14.27 ± 12.79. Based on the BDI results, 35 (62.5%) had a BDI score below 16 and were therefore not classified as being depressed, while seven (12.5%) patients suffered from severe depression (BDI > 47). Age and gender did not have any significant association with the BDI results (p = 0.52 and p = 0.67, respectively). The total prevalence of various degrees of depression was 30.8% in this study. We concluded that the noticeable rate of depression in thalassemic patients signifies the necessity for improving psychosocial care in this specific group of patients.