ABSTRAK Ruang Rawat Paru Rumah Sakit Umum Daerah dr. Zainoel Abidin (RSUDZA) Banda Aceh adalah salah satu ruang yang tak dapat terhindar dari terjadinya infeksi nosokomial. Ruang Rawat Paru memiliki tingkat kontaminasi bioaerosol yang tinggi, yang berasal dari droplet penderita. Penelitian ini bertujuan untuk menentukan indeks kuman udara di Ruang Rawat Paru RSUDZA Banda Aceh. Rancangan penelitian ini adalah observasional laboratorium menggunakan metode passive air sampling. Media Plate Count Agar (PCA) diletakkan pada area tertentu di ruang rawat paru selama 30 menit dalam keadaan terbuka, lalu diinkubasi pada suhu 370 C selama 24 jam. Pengamatan dilakukan terhadap jumlah kuman yang tumbuh di permukaan media. Hasil pengamatan dikonversikan ke dalam CFU/m3 berdasarkan Koch Sedimentation Method. Hasil penelitian menunjukkan bahwa indeks kuman udara di Ruang Rawat Paru RSUDZA melebihi kapasitas yang telah ditetapkan dalam Kepmenkes RI No.1204/SK/X/2004, yaitu melebihi 500 CFU/m3. Kata kunci : CFU/m3 , passive air sampling, droplet, indeks kuman.   ABSTRACT The Pulmonary Ward of dr. Zainoel Abidin General Hospital (RSUDZA) Banda Aceh is a ward that is indisputably affected by nosocomial infection. Pulmonary Ward has a high level of bioaerosol contamination from droplets of patients. The study aimed to determine of bacterial index in the air in Pulmonary Ward of RSUDZA of Banda Aceh. The research design of this study was laboratory observation design with passive air sampling method. The medium of Plate Count Agar (PCA) was placed on certain areas in the pulmonary ward for 30 minutes in the open air, then it was incubated on the degree of 370 C for 24 hours. The observation was conducted to count the amount of germs that grew on the surface of medium. The result of observation was converted to CFU/m3 based on Koch’s Sedimentation Method. The result of the study showed that the bacterial index in the air in Pulmonary Ward of RSUDZA exceeded the number of capacity mentioned in the decree of the minister of Health of the Republik of Indonesia No.1204/SK/X/2004, which is over than 500 CFU/m3. Keyword : CFU/m3, passive air sampling, droplet, bacterial index.