Acinetobacter baumannii je oportunistički patogen koji izaziva infekcije imunosuprimiranih bolesnika. S obzirom da je nedovoljno podataka o uspješnosti preživljavanja ovog patogena u prirodnom okolišu, cilj rada bio je odrediti stopu preživljavanja A. baumannii u različitim tipovima voda. Tri izolata A. baumannii višestruko rezistentnih na antibiotike inokulirana su u izvorsku, morsku i izlaznu vodu (efluent) uređaja za pročišćavanje otpadnih voda, te inkubirana na 20°C tijekom 50 dana. U izvorskoj vodi broj vijabilnih A. baumannii bio je konstantan sa stopom preživljavanja 92% nakon 50 dana. U morskoj vodi zabilježen je pad broja bakterija sa stopom preživljavanja 67% nakon 50 dana. U efluentu je došlo do umnažanja bakterija, te je broj A. baumannii bio veći od inicijalnog broja i nakon 50 dana praćenja. Umnažanje te bolje preživljavanje A. baumannii u efluentu u odnosu na izvorsku ili morsku vodu objašnjava se većom dostupnošću nutrijenata. A. baumannii višestruko rezistentni na antibiotike sposobni su preživjeti u različitom vodenom okolišu kroz duže vrijeme, što predstavlja mogućnost njihovog širenja putem voda u prirodni okoliš..; Acinetobacter baumannii is an opportunistic bacterial pathogen which causes infections in immunosuppressed patients. Considering insufficient data on the survival success rate of this pathogen in the natural environment, the purpose of this paper was to determine the A. baumannii survival rate in different water types. Three A. baumannii isolates with multiple antibiotic resistance multiply were inoculated in spring water, sea water and wastewater treatment plant effluent and incubated on 20°C in the period of 50 days. The number of viable A. baumannii in spring water was constant, with a survival rate of 92% after 50 days. In sea water, there was a recorded decrease of the bacterial numbers with a survival rate of 67% after 50 days. The bacteria in the effluent multiplied, and the number of A. baumannii was higher than the initial number even after 50 days of monitoring. The multiplication of bacteria and improved survival of A. baumannii in the effluent in comparison to spring or sea water is attributed to higher nutrient availability. A. baumannii with multiple antibiotic resistance can survive in different aquatic environments for a longer time period, which provides an opportunity for its spreading through water into the natural environment.