Pathological laughter is defined as uncontrollable and inappropriate laughter unrelated to an emotion or a mood. This symptom can reveal a stroke. ⋯ We described the case of a 57-year-old patient who presented to the emergency department 2 h after a sudden onset of left hemiparesis preceded by pathological laughter. The left motor weakness was very discrete and underestimated because of severe behavioral changes, that is, laughter, joviality, and motor restlessness. Despite abnormal brain imaging results, symptoms were considered as atypical to evoke a stroke. The patient did not receive intravenous thrombolysis. Brain magnetic resonance imaging performed 2 days after admission confirmed the diagnosis of stroke. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians are at the forefront of stroke management. They should be aware that the initial symptom of a stroke can be atypical and lead to misunderstanding the diagnosis. Because the treatment of stroke requires the fastest care, it is important for emergency physicians to know that sudden behavioral troubles and pathological laughter can reveal strokes.