Introduction:A postoperative cervical hematoma is a relatively rare, but potentially life-threatening complication after thyroid surgery. However, few cases with delayed manifestation after discharge of the patient are available in the literature. Case report: A 63-year-old Caucasian woman underwent total thyroidectomy for recurrent benign nodular goitre. She was discharged on the next day in good condition. On the third postoperative day, she was brought to the emergency unconscious with respiratory distress and enormous swelling of the neck. She was reoperated immediately, and postoperative hematoma due to bleeding from a small branch of the left superior thyroid artery was found. Definitive hemostasis was done. She stayed ten days in the ICU on artificial ventilation until the swelling was relieved. Due to signs of infection the wound was opened and treated with negative pressure wound therapy at regular intervals. After extubation, she was found to have phonation and eyesight disorders, fully recovered by conservative treatment in three weeks. The overall length of hospital stay was 41 days, and she was discharged in good condition. Conclusion: Very rarely, a delayed manifestation of postoperative bleeding after thyroid surgery could be seen. In the light of one-day surgery, the real danger is the possible delay of life-saving surgery, and this should always be kept in mind. Unfortunately, as of today, no reliable predictive signs are heralding delayed bleeding. The prompt surgical re-intervention is of paramount importance for the successful outcome. In this case, we successfully managed the infection with negative pressure wound therapy with white foam, thus preventing life-threatening neck phlegmon and mediastinitis.