Ankylosing spondylitis (AS) and multiple sclerosis (MS) are two different chronic inflammatory autoimmune conditions with unclear etiopathogenesis. One is a rheumatological disorder while the other is a neurological one. Current literature on an association between these two conditions is limited. Furthermore, early recognition of potential cases with both conditions co-existing is important as there have been very rare reports on the occurrence of demyelinating diseases or unmasking of latent MS in patients with ankylosing spondylitis treated with anti-TNFα. This has important therapeutic implications for patients at such risk.