One of the rare reasons for acute testicular pain is spermatic vein thrombosis. In the literature, the right side is much less involved than the left side. We report a case of a common symptom with a rare clinical feature. A 28-year-old man presented with acute testicular pain and swelling. Ultrasonography (US) showed focal venous thrombus at the level of the internal ring. The symptoms were resolved after anti-inflammatory therapy, but thrombosis was not. Due to the uncommon existence of spermatic vein thrombosis, the emergency department should be aware of misdiagnosis and the right therapy modalities.