In this study monthly aerosol samples collected at Erbil city, Iraq, throughout 2008-2009 yielded significant concentration of viable (culture forming) bacteria and fungi only when the dust was present. The results indicated the concentration of total bacteria was ranged from 3×10⁴ to 36×10⁶ CFU/g, and concentration of fungi varied a wide range from 6×10³ to 36×10³ CFU/g. The dominant group of bacteria isolated from the dust was Pseudomonas 25.6%, including P. corrugate, P. diminuta, P. marginata and P. agaramicus, followed by Zanthomonas 17.9%, including Z. orgzae, Staphylococcus 12.8%, including S. xylosus, S. epidermidis, S. homonis and S. cohini, Bacillus 10.2%, including B. subtilis and B. licheniformis, Curtobacterium, Micrococcus and Streptococcus 5.1%, Ctrubacterium, Rhodococcus and Agrobacterium 3.4%. Our data also confirms the existence of Aspergillus which comprised 23.4% of fungi colonies, followed by Penicillium 12.8%, Emerciella sp. 10.62%, Tetracoccosporium, Eurotium sp. 8.51%, Rhizopus sp., Sterile fungus, Trichocladium sp. 6.4%, Alternaria sp., Phoma sp., Yeast, Curvularia sp., Ascochyta sp., Taeniolella sp., Trichophyton, Fusarium sp., 2.12% of total isolated fungi.