A survey was conducted to measure concentration of airborne microbe in a hospital using RSC air sampler during October~November 1991.The result was as follows: 1) In an agar strip GK-A media for total counts of microbial particles. The highest count were 1384 CFU/m$^3$ in the main lobby, followed by 912 CFU/m$^3$, in the obstetric room, 688 CFU/m$^3$ in 1CU. By gram staining, the distribution for organisms in the air were shown 74.1% in gram possitive cocci followed by 16.8%, in gram possitive bacilli 6.7% in gram negative bacilli and 4.7% in yeast, but low organism was detected in recovery room with 194 CFU/m$^3$. 2) In agar strip S media for Staphylococci the count at the main lobby was detected in the recovery room with 92 CFU/m$^3$, Tests of coagulase were negative Staphylococci with 78%, and positive Staphylococci with 22%. The Staphylococci were highly resistance to penicillin, ampicillin and sensitive to amikacin, cefazolin, gentamycin and chloramphenicol. 3) In agar strip C media for coliform bacteria the colony counts at the main lobby was 139 CFU/m$^3$ and treatment room was 190 CFU/m$^3$, most frequently isolated microorganisms were non fermentative bacilli. 4) In agar strip HS media for yeast and molds. Most frequently colony counts 17~76 CFU/m$^3$, 0.5% lactophenol cotton blue stains were shown unidentified 77.2%, 8.1%, in Penicillium 8.1% in Aspergillus, and 3.8% in mucor.