Today, one of the most common methods used in the emergency room or intensive care unit (ICU) in patients is the Seldinger technique to access the central venous system, shunting for hemodialysis, intra-aortic balloon pump, or arterial insertion. Accidental leaving of the guide wire is an uncommon but important complication that can occur as a result of an incorrect technique, and it is sometimes found accidentally or due to complications years after the procedure. The case is a 53-year-old patient who underwent aortic valve replacement with a mechanical valve and mitral valve repair with a ring 12 years ago and was treated with warfarin. Two years after the heart surgery, due to chronic renal failure, the patient underwent dialysis, and after the preparation of an arteriovenous fistula, he underwent stenting. After approximately ten years, the patient developed fever, chills, and shortness of breath. During the examination, endocarditis was diagnosed, and a part of the aortic valve was released. There was a severe paravalvular leak in the aortic valve, and an abscess was formed in the aorta root. We also noticed a forgotten guide wire in the superior vena cava, right atrium, inferior vena cava, and hepatic vein, and echogenic masses were located on the guidewire. The diagnosis was confirmed by echocardiography, chest x-ray, and phenocopy. After antibiotic therapy, the patients underwent heart surgery, aortic valve replacement, and aortic root repair, and the guidewire was removed (70 cm long). Unfortunately, despite all measures, the patient died a few days after the surgery. Due to complications, a forgotten guidewire should be removed immediately after diagnosis. The preferred intervention is the removal of the guidewire by endovascular interventions, but surgical treatment should also be considered in some cases.