To survey the causes, characteristics, and outcomes of malpractice litigation resulting from injuries sustained during endoscopic sinus surgery (ESS). A retrospective analysis of United States state and federal civil litigation involving injuries resulting from ESS. Sources were state and federal court decisions and jury verdict reports accessed through a computerized legal database. The 41 cases were decided or settled between 1990 and 2003. The cases and reports were analyzed for pertinent data regarding plaintiffs, defendants, allegations of wrongdoing, resulting injury, expert witnesses, and resulting verdict or settlement. Correlation between severity of injury and case outcome was analyzed. All suits reviewed involved ESS. Many cases included multiple causes of action, or types of malpractice, including negligent technique, 31 (76%); lack of informed consent, 15 (37%); and wrongful death, 2 (5%). The defendant-physician specialty was overwhelmingly otolaryngology, 40 (98%). The most common presenting complaint, or indication for surgery, was chronic sinusitis, 30 (73%). The injuries caused by surgery were frequently multiple, including cerebrospinal fluid (CSF) leak, 10 (24%); brain damage, 6 (15%); diplopia, 7 (17%); and death, 2 (5%). The majority of cases reviewed (83%) resulted in a verdict rather than settlement. The result of the verdict or settlement was 17 (41%) in favor of the plaintiff, 23 (56%) in favor of the defendant, and 1 (2%) unknown. The average award was 751,275 dollars, with a median of 410,239 dollars and a range of 61,000 dollars to 2,870,000 dollars. This is the first study to review malpractice litigation resulting from injuries sustained during ESS and shows a hitherto unexpected pattern between severity of injury and case outcome.