Sinusitis has been reported as a complication of sinus lift surgery. Obstruction of the sinus outflow tract by mucosal edema and particulate graft material may result in sinusitis. Two main surgical procedures have been proposed for the treatment of associated infectious complications; inferior meatal antrostomy and functional endoscopic sinus surgery through transnasal approach. We performed superior lateral wall antrostomy through introral approach in patient suffering from the sinusitis after sinus floor augmentation and implant installation. This procedure permitted easier access to the maxillary sinus for treat sinusitis caused by sinus lifting.