Research shows that endothelin (ET)-traps are a potential therapy for diabetes. Given that type 1 diabetes mellitus (T1DM) is an autoimmune disorder, ET-traps could also have an efficacious, therapeutic effect on other autoimmune diseases associated with pathologically elevated ET-1. Here, we describe those different autoimmune diseases that might benefit from a tool such as ET-traps, which potently sequester these elevated levels of ET-1. We also discuss the current use of ET receptor (ETR) antagonists and the associated adverse effects, and how ET-traps are associated with no toxicity and potentially offer a superior alternative. ET-traps could be used against different autoimmune diseases and, therefore, are a novel therapeutic tool for such conditions.