Microbial contamination of hospital surfaces may be a source of infection for hospitalized patients. We evaluated the efficacy of Glosair™ 400 against two American Type Culture Collection strains and 18 clinical isolates, placed on glass germ-carriers. Carriers were left to air-dry for 60min and then exposed to a cycle before detection of any surviving micro-organisms. Antibiotic-susceptible Gram-negative bacilli were less susceptible (although not significantly) to this technique than resistant Gram-negative bacilli or Gram-positive cocci and yeasts (3, 3.4 and 4.6 log₁₀ reduction, respectively). In conclusion, in areas that had not been cleaned, aerosolized hydrogen peroxide obtained >3 log₁₀ mean destruction of patients' micro-organisms.