Background Vasoregulatory autoantibodies including autoantibodies targeting G‐protein–coupled receptors might play a functional role in vascular diseases. We investigated the impact of vasoregulatory autoantibodies on clinical outcome after ischemic stroke. Methods and Results Data were used from the PROSCIS‐B (Prospective Cohort With Incident Stroke–Berlin). Autoantibody‐targeting receptors such as angiotensin II type 1 receptor (AT1R), endothelin‐1 type A receptor, complement factor‐3 and ‐5 receptors, vascular endothelial growth factor receptor‐1 and ‐2, vascular endothelial growth factor A and factor B were measured. We explored associations of high antibody levels with (1) poor functional outcome defined as modified Rankin Scale >2 or Barthel Index