This study was conducted to determine whether the hospital devices and materials used for the examination and treatment of patients play a role in the outbreaks of infection in hospitals. Environmental sampling was performed to find the possible sources of septicemia at the neonatal intensive care unit (NICU). Environmental sampling results and blood culture records from the outbreak areas were compared to determine if they had any relationship with each other. Semisolid and solid samples were compared with liquid samples for positive cultures using a chi-square test. Statistical significance was accepted at P<0.05. The results showed that liquid sources were more frequent media for infectious agents (OR, 8.75; chi-square, 0.0278). The most common cultured microorganisms were coagulase negative Staphylococcus and Klebsiella pneumoniae, which were responsible for septicemias at NICU. There were strong relationships between environmental culture results and the agents responsible for the outbreak of septicemia at the NICU. The formula heater at the pediatrics clinic also revealed the same microorganisms with the blood cultures of 3 patients in the same clinic. Although there are matches between the environmental sampling and blood culture records in our study, there is a need for further studies. We conclude that moist areas and liquid environments must be regularly checked for pathogen microorganisms. Instead of using heated water to sterilize infant formula, dry air sterilization should be used. Liquid media like oxygen reservoir solution and antiseptic solutions must be checked for contamination and should be changed periodically.