Total knee arthroplasty (TKA), particularly when performed as a simultaneous bilateral procedure, theoretically increases the risk for entry of fat globules into the blood stream. The frequency of cerebral fat embolism syndrome (CFES) was retrospectively investigated among 2345 simultaneous bilateral TKA procedures performed from August 2006 to May 2010. During that period, 9 patients presented with neurologic deficits after surgery and underwent brain magnetic resonance imaging. For identification of CFES among them, we used both magnetic resonance imaging findings and clinical criteria modified from the original one of Gurd and Wilson (J Bone Joint Surg Br 1974; 56B:408). Four patients fulfilled the modified criteria. The overall incidence of CFES occurring after simultaneous bilateral TKA was 0.17%. Cerebral fat embolism syndrome should be ruled out, although rare, in patients who present with neurologic impairment after TKA.