Pemphigus vulgaris (PV) is an autoimmune bullous and erosive mucocutaneous disease. Rarely, it occurs in patients with other autoimmune disease. The relation between PV and neurological disorders is unclear and needs to be more studied. Here, we report a case of amyotrophic lateral sclerosis (ALS), followed by dermatologic involvement. Histopathological evidence and direct immunofluorescence are consistent with PV. Systemic corticosteroid and azathioprine were effective in the treatment of mucocutaneous lesions. PV seems to be accidentally associated with ALS. Expression of major histocompatibility complex Class II in autoimmune disease and production of autoantibodies have been proposed to describe the association of PV with ALS.