A 36-year-old woman with a left lung tumor was referred to our hospital since a pathological diagnosis had not been obtained at a previous medical institution. We carried out CT-guided percutaneous lung biopsy with an 18-gauge needle and obtained four samples. Immunological staining revealed the specimens to be CD30- and PAX5-positive, with large dysplastic lymphocytes negative for Bob-1 and Oct-2 with a background of small lymphocytes and eosinophils. Primary pulmonary Hodgkin lymphoma (PPHL) was diagnosed. Although PPHL is very rare, it should be included in the differential diagnosis of lung tumors and immunological staining with CD15 and CD30 is recommended. Furthermore, carefully planned CT-guided lung biopsy is useful for diagnosing PPHL.