Bacteria coexist in moisture-damaged building materials with fungi and could contribute to the adverse health outcomes associated with exposure. However, much less information is available on the bacterial communities in moisture damage buildings compared to that of mold. The aim of the proposed work is to investigate how the bacterial diversity differs between moisture-damaged buildings and undamaged reference buildings. Pyrosequencing will be used to determine the bacterial diversity in dust samples collected from moisture-damaged buildings and undamaged reference buildings in the Cincinnati area. The use of the culture-independent pyrosequencing method is expected to indentify individual major strains of bacteria specifically associated with moisture-damaged buildings that might normally be missed by culture-based methods. Pyrosequencing is a time- and cost-efficient sequencing technique that employs coupled enzymatic reactions to detect inorganic pyrophosphate (PPi) released as a result of nucleotide incorporation during DNA synthesis. The results are expected lead to improved early prediction and cost-effective testing of microbial contamination in buildings. The proposed study is also expected to lead to a better understanding of the association between building moisture damage and respiratory symptoms, namely which specific bacterial species could contribute to these respiratory symptoms.