In countries that are humid throughout the year, mold is a common problem that can occur even on a computer keyboard. Mold is smelly and may damage computer keyboards. It is caused by fungal spores in the air. It can also affect occupants’ health. This study aimed to evaluate the efficiency of potassium sorbate as a biocide to reduce the viability of indoor airborne fungus in a higher educational building of computer studies of a university located at the southern Peninsular Malaysia. Malt extract agar (MEA) was incorporated with the biocide and was used for air sampling of fungi at 3 different sites of the building including outdoors. The effectiveness of the biocide was evaluated by comparing the treated agar against the untreated agar. It was clearly shown that the biocide can effectively reduce the number of colony forming units of the airborne fungi at all 3 tested sites (>70% in average) on the treated culture media, while the untreated media at all three sites was colonized by fungi with different concentrations. Copyright © 2014 Penerbit Akademia Baru All rights reserved.