Résumé : Objective: The authors report on a patient whose unilateral chronic maxillary sinusitis was caused by the migration of a silastic implant used for orbital floor repair. Case report: A 32-year-old woman presented with a three-year history of right-sided maxillary discomfort that was associated with a purulent discharge. Her medical history included chronic allergic rhinitis and the placement of a silastic implant after a right orbital floor fracture at the age of 14. The silastic implant was then removed endoscopically in a right maxillary sinus meatotomy. The symptoms improved within three weeks after surgery. Conclusion: Orbital implant migration is a rare cause of chronic unilateral sinusitis, and it must be suspected on the basis of a careful anamnesis, appropriate clinical examination, and sinus computed tomography. Misdiagnosing such a condition may increase patient morbidity by leading to inappropriate treatment.