Technical Abstract: A study was conducted to determine airborne microorganisms in three different types of shell egg processing operations (in-line, off-line and mixed operations). Sampling sites were evaluated from each facility on three different days (replication) during the same week. Four air samples were drawn from each sampling site on a given day. Sampling sites, where applicable, included areas in or near the following on-site locations: hen house (in-line and mixed operations), farm transition room (in-line and mixed operations), egg washers, egg dryer, packer heads, post-processing cooler, nest-run cooler (off-line and mixed operations), loading dock and dry storage. Type of operation (in-line, off-line or mixed), sampling site and the interaction between operation and site had a significant effect on the number of total aerobic bacteria, molds/yeasts, coliforms and pseudomonads recovered. Highest counts for total aerobic bacteria, molds/yeasts, and coliforms were found in the hen house. Highest counts for pseudomonads were found in the hen house and behind the egg washers. Lowest counts for total aerobic bacteria and molds/yeast were found in the post-processing cooler. Few samples in the post-processing coolers, nest-run coolers, loading docks and dry storage areas tested positive for coliforms) and pseudomonads. Data gathered during this study may be useful in identifying the sources and levels of airborne contaminates in commercial shell egg processing facilities.