Background: Superior vena cava syndrome (SVCO) is caused by compression of superior vena cava and restriction of blood flow to the heart. The most common underlying condition in cancer patients is lung cancer or other malignancy expanding in the upper mediastinum. SVCO belongs to oncological emergencies and requires a prompt diagnostic work‑ up and treatment. Case 1: A 79‑year‑ old man with a history of right‑ sided stage IIIB non‑small cell lung cancer, after two cycles of chemotherapy, was admitted to hospital with clinical signs of SVCO. The initial radiotherapy brought no relief of symptoms and due to deterioration of patient‘s status during the treatment we proceeded to self‑ expanding caval stent insertion. This was followed by immediate resolution of SVCO symptoms. Case 2: In the second case we describe a 56‑year‑ old female with a newly diagnosed diffuse large B cell lymphoma who presented with SVCO symptoms when referred to our outpatient chemotherapy department. She had no history of previous treatment and she complained of a rapid face and eye‑lid edema and intractable cough in the last two days. CT scan revealed mediastinal mass compressing the superior vena cava. Urgent anti‑lymphoma chemotherapy (RCHOP schedule) was commenced and yielded quick resolution of her symptoms. Conclusion: Superior vena cava syndrome is a medical emergency in oncological patients usually caused by external compression of cava by lung cancer, lymphoma, other tumors, less frequently, from a thrombosis of indwelling central venous catheter. Multidisciplinary cooperation among radiation and medical oncologists and interventional radiologists is needed in order to provide an early treatment without an undue delay.