Development of intracranial dural sinus thrombosis in the postpartum period has been attributed to the hypercoagulable state of pregnancy. With increasing recognition of the role of the vitamin K-dependent proteins, protein C and protein S, in intracranial venous and arterial thrombotic events, our understanding of the cause of thrombotic events has improved. We report a patient who developed a superior sagittal sinus thrombosis in the second week postpartum, associated with a dysfunctional protein C and a decreased free protein S concentration.