When a patient presents with acute neurological deficit, ischemic stroke is often assumed. However, a functional neurological disorder (FND) can also present with stroke-like symptoms. FND is a multifactorial condition to which biological, psychological and social factors predispose. The distinction between FND and acute ischemic stroke can be challenging, but is very important because fast reperfusion treatment is indicated for ischemic stroke. We show the specific features of FND in history and neurologic examination to pay attention to. Furthermore, we discuss the use of additional investigation to support the diagnosis. We describe two patients with an acute neurological deficit: a 34-year-old male with hemiparesis and speech disturbances due to FND, and a 51-year-old male with hemiparesis and hemi-ataxia due to ischemic stroke. These 2 patients demonstrate how challenging the distinction between FND and stroke may be.