This study investigated the incidence and clinical significance of postoperative fever in 118 consecutive patients undergoing 141 total knee arthroplasties (TKAs). A postoperative fever was recorded in 63 (66%) of 95 unilateral and 17 (74%) of 23 bilateral TKA patients. Nine of the unilateral and five bilateral TKA patients developed positive clinical or laboratory findings to explain the pyrexia. Unilateral TKA patients who experienced postoperative fever were statistically more likely to have a complication in the immediate postoperative period. None of the surgical variables examined had any predictive value on the incidence of postoperative fever. Aggressive pulmonary toilet, repeated physical examinations, and urine analysis are recommended when evaluating TKA patients with postoperative fever. Fever following TKA was common and was not necessarily a contraindication to discharge.