The level of airborne microbes in hospitals is unknown in the United Arab Emirates (UAE), An investigation of the quantity and quality of airborne microbes in Al-Ain hospital, UAE, was carried out to establish standards for future reference. Using a bacteria mechanical air sampler, microbiological samples were collected from different hospital units. The bacterial and fungal isolates were enumerated and identified, The variables were coded, entered, and processed by the Statistical Packages for Social Sciences (SPSS) with p<0.05 considered the cutoff point. Ten groups of microorganisms isolated were either human or environmental bacteria and fungi. Environmental agents predominated and were not identified, Some units were significantly bacteriologically more contaminated than others but fungi were close in most wards. There were small numbers and quantities of potential pathogens. There were five genera of fungi isolated with a predominance of Aspergillus species but these were low. The intensive care unit (ICU) and operating theatre (OT) had low counts and significantly more human related than environmental microorganisms. The quantity and quality of the microbial population seem to be reasonable in this observation and will serve as references for future studies. Copyright (C) 1997 Elsevier Science Ltd.