Rationale:Delayed rupture of traumatic intracranial aneurysms is relatively rare, and traumatic anterior A4 segment aneurysms may be associated with trauma to the cerebral falx. The mortality rate in patients with delayed traumatic rupture of intracranial aneurysms is>50%. Therefore, early diagnosis and treatment are critical. Herein, we present a case of a patient who did not have an intracranial aneurysm on computed tomographic angiography (CTA) after admission. Subsequently, the patient consciousness deteriorated, and CTA revealed aneurysm and bleeding.Patient concerns:A 55-year-old man fell from a 3-meter-high truck and was unconscious. During the following few hours, the gradually regained consciousness. No intracranial aneurysms were found on CTA of the patient head immediately after admission.Diagnoses:The final diagnosis was delayed rupture of traumatic intracranial aneurysms.Interventions:The patient underwent endovascular and symptomatic treatments.Outcomes:The patient gradually recovered and was referred to the rehabilitation department for further treatment.Lessons:Considering the catastrophic consequences of the disease, we should review CTA or digital subtraction angiography many times after admission, and take appropriate surgical procedures in time.