Few studies have investigated fever secondary to underlying acute aortic dissection. A retrospective analysis of 59 patients was carried out. Diagnostic criteria for fever secondary to underlying aortic dissection were defined. Five patients had a clinical presentation consistent with inflammatory fever due to acute aortic dissection. The main features were: fever occurred within the first 48 hours, the variability in body temperature was significantly less than with infectious fever (P=.015), episodes of fever did not affect the patient's general clinical condition, microbiological tests gave negative results, there was no response to empirical antimicrobial treatment, and fever disappeared within 24 hours in those treated with indomethacin. In conclusion, fever due to acute aortic dissection has distinct characteristics that enable it to be distinguished from infectious fever. Good management of this condition should not involve unnecessary diagnostic tests, the inappropriate use of antimicrobials, or a delay in applying the therapeutic measures necessary to treat the underlying aortic dissection.