Historically, poliovirus infection has been an important cause of acute flaccid paralysis (AFP) worldwide; however, successful elimination of wild-type poliovirus in much of the world has highlighted the importance of other causes of AFP. Despite the evolving etiology, AFP surveillance in most developing countries still focuses on poliovirus detection and fails to detect many AFP cases, particularly among adults. We assessed 41 subjects self-reporting symptoms suggestive of AFP during a population-based health survey in the Department of Santa Rosa, Guatemala. Thirty-five (85%) of the suspected cases were not hospitalized. Most subjects (37) did not have features consistent with AFP or had other diagnoses explaining weakness. We identified two adults who had not received medical attention for a clinical illness consistent with Guillain-Barré syndrome, the most important cause of non-poliovirus AFP. Usual surveillance methods for AFP, particularly in developing countries, may underestimate the true burden of non-poliovirus AFP.