α-Synuclein (αS) is the main component of Lewy bodies from Parkinson’s disease. That αS binds to membranes is known, but the conformation it adopts is still unclear. Pulsed EPR on doubly spin-labeled variants of αS sheds light on the most likely structure. For αS bound to vesicles large enough to accommodate also the extended conformation, an antiparallel helix conformation is found. This suggests that the bent structure shown is the preferred conformation of αS on membranes.