We present a case of a 65-year-old female with choroidal melanoma, who developed an orbital hematoma following ruthenium-106 (¹⁰⁶Ru) plaque implantation. The patient, with a history of recurrent ipsilateral subconjunctival hemorrhages and arterial hypertension, experienced intense coughing immediately following the completion of surgery and extubation. Subsequently, she developed an orbital hematoma (confirmed by B-scan ultrasonography). Conservative management, including oral steroids and acetazolamide, was adopted. Plaque removal was challenging due to hematoma-induced restricted eyelid opening, but post-operative recovery was uneventful. Although potential suboptimal dosimetry raises concerns for long-term tumor control, short-term local tumor stability was observed at 6 months. To the best of our knowledge, this is the first report of such complication, highlighting the importance of vigilant post-operative monitoring to optimize treatment outcomes for ¹⁰⁶Ru brachytherapy.