Microorganisms in the air are part of the bioaerosol which is composed of different particles of biological substances, dust particles, bacteria cells and their portions, mould spores and a number of by-products of their metabolism. This research focuses on analysing the primary microclimate indicators (temperature and relative humidity) and the presence of microorganisms in the work environment (air). Measurements were taken after the process of sterilisation of infective waste over three months with the objective to determine the total number of aerobic mesophilic bacteria and the total number of moulds. The microclimate indicators were measured with an attested device. The study monitored the microbiological purity of the air in a given place using the sedimentation method, with samples subsequently processed in a microbiology lab in keeping with the prescribed standards. After incubation and following the counting of developed colonies on microbiological substrates (Tryptic soy agar and Sabouraud dextrose agar), different strains of bacteria and moulds were identified. The most common were Gram (+) sporogenes bacteria Micrococcus spp and Staphylococcus spp., and as for fungi the most commonly found were Aspergillus spp and Penicillium spp. It was found that temperature and relative humidity affect the total number of aerobic mesophilic bacteria and fungi which was confirmed using the Wilcoxon equivalent pairs test at the level of statistic significance p<0.05. SAŽETAK: Mikroorganizmi u zraku sastavni su dijelovi bioaerosola koji se sastoji od različitih čestica biološkog materijala, čestica prašine, bakterijskih stanica i njihovih dijelova, spora gljivica, te dijelova nusprodukata njihovog metabolizma. U ovome istraživanju analizirali su se osnovni pokazatelji mikroklime (temperatura i relativna vlažnost) kao i prisutnost mikroorganizama u radnom okolišu (zraku). Mjerenja su se obavljala poslije procesa sterilizacije infektivnog otpada tijekom tri mjeseca, a određivao se ukupan broj aerobno mezofilnih bakterija i ukupan broj gljiva. Pokazatelji mikroklime određivani su atestiranim uređajem. Ovom studijom pratila se mikrobiološka čistoća zraka, na određenom mjestu metodom sedimentacije, a uzorci su se poslije obrađivali u mikrobiološkom laboratoriju u skladu s propisanim normama. Nakon inkubacije i brojenja izraslih kolonija na mikrobiološkim podlogama (Tryptic soy agar i Sabouraud dextrose agar) identificirani su različiti rodovi bakterija i gljiva. Najčešće su bile zastupljene Gram (+) sporogene bakterije iz roda Micrococcus spp. i Staphylococcus spp., te rodovi gljiva Aspergillus spp. i Penicillium spp. Dokazano je da vrijednosti temperature i relativna vlažnost utječu na ukupan broj aerobno mezofilnih bakterija i gljiva što je potvrđeno Wilcoxonovim testom ekvivalentnih parova na razini statističke značajnosti p<0,05.