Context. Childhood cancer survival has increased substantially over the past few decades. However, long-term side effects associated with cancer treatment have also risen. Especially thyroid gland disorders are common. Objective and Design. The present retrospective cross-sectional study aimed to investigate risk factors of long-term TD in survivors of leukemia-lymphoma. Subjects and Methods. The study included 44 acute lymphoblastic leukemia (ALL) and 26 Hodgkin lymphoma survivors (HL). Abnormal laboratory and pathological ultrasonographic findings of the thyroid gland were accepted as a thyroid disorder. The possible causes of thyroid disorders were investigated. Results. Long-term thyroid disorder was found in 40% of the patients. This rate was higher in HL patients than in ALL (65% vs. 25%). Thyroid disorder was significantly more common in patients who received radiotherapy to the neck (57% vs. 17%). Radiotherapy to the neck area was the only significant determinant for thyroid disorders in the regression models [OR 33.17, 95% CI (2.76-398.9) p = 0.006]. However, HL remained significantly associated with TD in the logistic model performed using cancer type [OR 19.25, 95% CI (2.39-155.3) p = 0.006]. Conclusions. The study showed that radiotherapy applied to the neck was an essential risk factor for long-term TD in the average 6-year follow-up of cancer survivors. However, we recommend that childhood cancer survivors should be followed closely for a long time since long-term endocrine side effects were reported during longer than six years follow-up periods.