Optic neuritis is commonly associated with diseases such as Multiple Sclerosis, infections, taking special drugs, etc. but recently we have observed a patient that presented retro bulbar optic neuritis as a manifestation of antiphospholipid syndrome. A 35 y/o young woman with the history of chickenpox admitted to the Qhaem hospital (Mashhad, Iran) with the c/o progressive pain and blurred vision in the left eye. the brain MRI was normal. the VEP test demonstrated severe left optic neuritis and the right optic nerve was also mildly affected. the concentration of glucose, urea, electrolytes and CBC were WNL, but the presence of autoimmune antibodies in her blood proposed the probability of an autoimmune disease. she received Corton and Val acyclovir orally. After receiving Corton pulses her vision was moderately improved and she was released with some drug prescriptions. Also she was to perform vasculitis tests.13 days later, after consulting with the rheumatologist about the results of the vasculitis tests, she was referred to the neurology department again. she was undergoing 5 sessions plasma pheresis. Then, she was recharged with moderate general good feeling. According to this patient and other similar cases, for the patient that is affected by vasculitis and also have thrombocytopenia, but does not fulfill the criteria for lupus, antiphospholipid syndrome may be considered as a possible diagnose.