Although fatality from fat emboli syndrome following total knee arthroplasty has been reported, most cases occurred following the insertion of hinged prostheses and few are documented with detailed pathology. The authors present the case of a 75-year-old patient with long-standing rheumatoid arthritis who underwent a total condylar type total knee arthroplasty procedure using an intramedullary femoral alignment system and expired 6 hours following surgery. On autopsy he had multiple organ involvement with fat emboli. Especially with the present use of intramedullary alignment systems and the increasing numbers of one-stage bilateral total knee arthroplasty procedures the potential for this problem must be recognized so that early therapy can be instituted.