Postpartum arterial dissection combined with subarachnoid hemorrhage (SAH) is rare and its mechanism is uncertain. A 32 year-old woman had a delivery by cesarean section 12 days prior to admission to our hospital. From the first day of delivery, she breast-fed her baby, sitting with her head always turned to the right. Each feeding lasted around 2 hours. A bilateral throbbing headache began two days after childbirth, and intermittent numbness of the right face, chest and hand as well as weakness of the right hand developed nine days after giving birth. A physical examination revealed transient mild hypertension and right hemiparesis. Her cholesterol ranged from 204 to 263 mg/dl. Computed tomography, magnetic resonance angiography and duplex ultrasound disclosed left fronto-parietal junction SAH and dissections of the right internal carotid (ICA) and vertebral arteries. Our patient demonstrated (1) that postpartum arterial dissection was not limited to natural delivery, (2) postpartum SAH could occur with dissections of the contralateral extracranial carotid and vertebral arteries, and (3) that turning one's head always to the same side during breast-feeding might be a risk factor for this unusual stroke pattern.