Myringotomy and tube insertion, a common pediatric surgical procedure, is frequently complicated by purulent otorrhea. Many otolaryngologists routinely use topical antibiotics as prophylaxis against post-tympanostomy otorrhea. The aminoglycosides (neomycin sulfate, tobramycin and gentamicin) contained in commonly used topical antibiotics as well as components of the solutions have been shown to be ototoxic in animal studies. Although little reported evidence of ototoxicity in humans exists, sporadic reports of sensorineural hearing loss linked to topical antibiotic use do exist, and the potential for sensorineural hearing loss must be considered. The purpose of this study is to compare the rate of post-tympanostomy otorrhea in a double-blinded randomized trial using either topical Ciprofloxacin, with no reported ototoxicity, or Cortisporin as prophylaxis. One hundred patients (200 ears) between ages 7 months and 11 years with a diagnosis of recurrent otitis media or chronic otitis media undergoing tympanostomy tube insertion were randomized into two equal groups. Three drops of either drop A or B were placed into each ear at the time of tube insertion and then three times daily for 3 days. Patients were examined at 3 weeks and details of otorrhea were obtained. The rate of otorrhea was analyzed using chi-square. The overall rate of otorrhea was 39 ears (19.5%), 17 (17%) ears for the Cortisporin group and 22 (22%) for the Ciprofloxacin group. The difference in rate of otorrhea was not statistically significant (P=0.372, 95% confidence interval equals -6-16%). Our data suggest that topical Cortisporin offers no benefit over Ciprofloxacin for post-operative otorrhea prophylaxis. Therefore we recommend topical quinolone prophylaxis, which should eliminate concerns about ototoxicity, without sacrificing efficacy.