INTRODUCTION: Amyloidosis derived from transthyretin (TTR) molecules is typically caused by mutations of the TTR gene. METHODS: We describe an elderly patient with a severe length-dependent polyneuropathy that unexpectedly proved to be caused by wild-type transthyretin amyloidosis. RESULTS: The diagnosis was made by muscle biopsy, because no amyloid deposits were found in the biopsied nerve segment. Most cases of wild-type transthyretin amyloidosis occur in elderly patients with cardiomyopathy, but a few cases of polyneuropathy have been reported. CONCLUSIONS: This entity is especially noteworthy in light of emerging treatment options for hereditary transthyretin amyloidosis, which are likely to also be beneficial in wild-type disease.