Abstract: The diversity of airborne bacteria and fungi inside and outside the T3A cephalosporin production factory was studied using different microbiological techniques. Results of indoor aeromicrobiota showed complete absence of microbial units in the environment of aseptic filling machine (class A). The counts of microbes in the aseptic filling room (class B) as well as in gowning room (class C) and in the rooms designed for preparation and filling of non-sterile cephalosporin capsules and dry mix (class D) were within the limits recommended by WHO guidelines. The count of outdoor airborne microbes using the air sampler technique was about 7-folds that of indoor air (6240 versus 854 colonies). The number of species isolated from the outdoor air was higher than that of indoor air (17 versus 10 species). Microbiological analysis of water showed much lower counts of microbes in purified water than in city water samples (80 versus 761 colonies). Microbes were also isolated from 60% of non-sterile finished products but they were completely absent in all samples of sterile finished products. The majority of microbial species recovered from the non-sterile finished products were found in both indoor and outdoor air of the cephalosporin-manufacturing factory but only four of these microbes were obtained from the purified water samples. Common microbial contaminants, namely species of Bacillus, Staphylococcus, Aspergillus, Penicillium, and Cladosporium were encountered. Key words: T3A, cephalosporin factory, air and water bacteria and fungi.