A 6-month-old, female, intact, domestic shorthair cat presented to the Cornell University Hospital for Animals Internal Medicine Service on January 13, 2011 for further evaluation of abdominal coagulation factors detected on blood work by the referring veterinarian. Initially, the cat presented to the referring veterinarian for a elective ovariohysterectomy when pre-surgical blood work revealed a prolonged activated partial thromboplastin time with a normal prothrombin time. Coagulation factor analysis, performed by the Cornell University Coagulation Lab, revealed a deficiency of factor XI. On presentation the cat appeared to be in good health, and had not shown any clinical signs of coagulopathy. Physical exam revealed a small, firm mass over the right medial saphenous vein, presumably a fibrous scar tissue from a previous venipuncture site. During hospitalization, the patient was blood typed and was a type A. She received a pre-operative fresh frozen plasma transfusion. A routine ovariohysterectomy was performed without complications, and the patient received a second fresh frozen plasma transfusion post-operatively. The patient recovered smoothly and was discharged to the owners three days later.