Background. Chylothorax is defined as chyle entering the pleural space. The most common causes of chylothorax are lymphoma followed by bronchogenic carcinoma and trauma. Case report. We report a case of chylothorax in a patient with Hodgkin's lymphoma. A 28-year old man was admitted to the hospital with exertional dyspnea and dry cough. A chest X-ray showed the large opacity on the left side suggesting to the presence of pleural effusion. Methods. The effusion was drained, and biochemical tests of the pleural fluid revealed high contents of triglycerides and, hence, confirmed the diagnosis of chylothorax. Cytology of the pleural fluid showed no evidence of Hodgkin's cells. Computer tomography scans of the chest and abdomen exhibited the presence of a soft tissue mass located in the left mediastinum. Mediastinal mass biopsy led to diagnosis of Hodgkin's lymphoma of the nodular sclerosis subtype. The patient received the standard treatment with two cycles of chemotherapy with prednisolone, doxorubicin, cyclophosphamide, vincristine, bleomycin, procarbazine, and etoposide (BEACOPP), followed by an additional two cycles of therapy with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). Results. After one cycle of chemotherapy, chylothorax initially decreased. Unfortunately, during the following courses of chemotherapy, the pleural effusion reoccurred and repeated pleural taps were necessary. According to the treatment protocol, radiation of the mediastinal bulk was performed after chemotherapy. Now, nearly one year after completion of radiotherapy, the chylothorax has significantly regressed and no further thoracocenteses were necessary. Conclusion. The case reveals an example of left-sided chylothorax as the first manifestation of Hodgkin's lymphoma in a young patient. In this case, radiotherapy was shown to be an effective treatment option for lymphoma-associated chylothorax unresponsive to chemotherapy.