This study examines the effects and influences of fumigation on the antimicrobial treatment of excavated dresses in two different museum settings using chemical composite of Methyl Bromide and Ethylene Oxide. The microbial test indicated that the prewashed samples contained Micrococcus, Bacillus, Staphylococcus, and some unidentified fungi and that the total number of microbes decreased after washing. While it was observed that most germs were removed immediately after fumigation, Bacillus was still found and its number even increased. After 5 months, the number of microbes found in Museum A was smaller than Museum B, which shows that Museum A equipped with better environment control facility was superior to Museum. B in terms of exhibition and preservation of dresses against organic damages. In addition, the result indicates that fumigation is an effective measure against the growth and reproduction of microorganisms, considering that the number of microorganisms decreased after fumigation. The color of test sample showed immediate change after fumigation but color difference became stabilized and decreased with the passage of time. The test samples from both museums showed similar patterns.