Objective. Arachnoiditis is an inflammatory process resulting with the fibrosis of arachnoid mater. It can vary in severity from mild thickenings to catastrophic adhesions that ruins subarachnoid space. As a result, arachnoid cysts can be formed. Arachnoid cyst induced by symptomatic spinal arachnoiditis is a rare complication of subarachnoid haemorrhages. In this article, we aimed to present a case of spinal arachnoid cyst formation following subarachnoid haemorrhage and examine similar cases in the literature. Case Report. Forty-six years old, previously healthy female patient has been treated medically for headaches due to perimesencephalic subarachnoid bleeding. Approximately two and a half months later, she started to have severe headaches and diplopia. We detected hydrocephalus and performed ventriculoperitoneal shunt surgery. Two months later, she started to have complaints of weakness in her lower extremities. On neurological examination, she had paraparesis and on spinal magnetic resonance imaging she had an arachnoid cyst lengthening from C7 to 12 and compressing the spinal cord posteriorly. We performed partial laminectomy, drainage of arachnoid cyst and replacement of cystopleural T tube shunt. On follow-up, her lower extremity strength has ameliorated. She was taken into a physical therapy and rehabilitation programme. Three months later she was able to walk with a crutch. Conclusion. Subarachnoiditis and associated arachnoid cyst can cause severe morbidity. This rare situation (which especially occurs following subarachnoid haemorrhage of posterior fossa) should be known and physicians should keep in mind that it requires urgent surgical procedure.