The effect of prophylactic aminoglycoside antibiotics upon vestibular function was studied using a double-blind protocol in a group of head and neck cancer patients scheduled for contaminated (skin-to-mucosa) surgical procedures. The amplitude (gain) of vestibular responses to rotation temporarily declined in 12 of 25 patients postoperatively. There was no correlation between temporary decline in vestibular response and administration of gentamicin, clindamycin, and cefazolin. After a recovery period of one to three months, none of the patients showed evidence of vestibular aminoglycoside ototoxicity. The transient reduction in vestibular responses to rotary stimuli was possibly related to the use of analgesics, anesthetic agents, or radical neck dissection procedures. The importance of repeat measures and proper timing of vestibular ototoxic monitoring procedures in a surgical patient population was demonstrated by this study. Results of this study may also impact interpretation of findings from certain surgical procedures performed for control of vertigo.