The incidence and clinical relevance of subdural haematoma (SDH) in patients with spontaneous intracranial hypotension (SIH) remain undetermined. We reviewed 40 consecutive SIH patients (18 female, 22 male) in a tertiary hospital. Eight (20%) of them had SDH and nine (23%), non-haemorrhagic subdural collections. The presence of SDH was associated with higher frequencies of male gender, recurrence of severe headache and neurological deficits. Outcomes were satisfactory after supportive care or epidural blood patches except for one SDH patient, who developed transtentorial herniation resulting in Duret haemorrhage and infarctions of bilateral posterior cerebral artery territories. In conclusion, subdural fluid collections were common in patients with SIH. SDH was associated with headache worsening or neurological deficits. Patients with SDH generally recovered well; however, serious sequela might occur.