Treatment for primary mediastinal lymphoma generally involves chemotherapy and radiotherapy, and treatment regimens depend on histologic subtypes of lymphoma. The histologic subtype of lymphoma is mostly determined by computed tomography (CT)-guided core-needle biopsy or surgical procedures, including thoracotomy, thoracoscopy and mediastinoscopy. We describe the clinicopathologic features and diagnostic procedures of 8 cases of primary mediastinal lymphoma. The male-to-female ratio was 1:1, and median age at diagnosis was 27 years. The median size of the primary mediastinal tumor on CT was 8.5 cm. Five patients were diagnosed by CT-guided core-needle biopsy, 1 by open biopsy and 2 by surgery. Three patients were diagnosed with nodular sclerosis Hodgkin lymphoma, 3 with mediastinal diffuse large B-cell lymphoma, 1 with precursor T-lymphoblastic leukemia/lymphoma and 1 with thymic extranodal marginal zone B-cell lymphoma. According to their histological subtypes, 5 patients were treated with chemoradiotherapy, 2 patients with chemotherapy and 1 patient of thymic extranodal marginal zone B-cell lymphoma with surgery alone. All patients survived in the median follow-up of 34.5 months. Appropriate biopsy procedure should be performed in patients with suspected mediastinal lymphoma.