Multiple sclerosis is an autoimmune central nervous system disease that affects young adults and causes inflammation, demyelination and axonal loss. Within the common relapsing-remitting course of the disease patients develop various neurological symptoms that lead to significant disability overtime. The anti-phospholipid syndrome, similarly to multiple sclerosis, appears in young adults and is characterized by thromboembolic events and pregnancy complications. The overlay between these two diseases and the ability to correctly diagnose or differentiate between them is sometimes difficult. The current review approaches this problem and discusses whether multiple sclerosis and anti-phospholipid syndrome are actually one or two diseases.