We present two patients with neuromyelitis optica (NMO; Devic's syndrome), one associated with systemic lupus erythematosus and the other with Hashimoto thyroiditis. Devic's syndrome, whose initial symptoms and signs mimic those of multiple sclerosis, can be associated with other autoimmune diseases. We emphasize the importance of ruling out other entities throughout the follow-up. NMO is seldom described in patients with lupus, which may be due to the rare occurrence of this association sometimes leading to its misdiagnosis.