AbstractPurpose Late-Onset Pneumonia (LO-PNEU) is still the most important complication associated with the hospitalization of infants with very low birth weight (<1501 g). The purpose of this paper is to summarize the results of an ongoing surveillance program defining LO-PNEU as associated or not associated with respiratory support in the \{NICU\} and distribution of causative pathogens from the Polish Neonatology Surveillance Network (PNSN). Materials and methods Surveillance of infections was conducted in the years 2009–2011 at six Polish NICUs. Results The incidence was 3.1/1000 \{NICU\} patient days (pds). The mean gestational age and birth weight among infants with LO-PNEU were significantly lower. The \{VAP\} incidence was of 18.2/1000 \{NICU\} pds for mechanically ventilated (MV) infants, while the rates for those receiving only \{CPAP\} were as low as 7.7/1000 \{NICU\} pds. \{MV\} significantly increased the risk of PNEU, but \{MV\} or \{CPAP\} for <10 days did not increase the risk of LO-PNEU. Significantly associated with LO-PNEU was the use of central or peripheral venous catheters and total parenteral nutrition for longer periods. Microorganisms isolated in cases of LO-PNEU were Gram-positive cocci (53.5%) and Gram-negative rods, with predominating E. coli. Non fermentative bacilli were significantly more frequent in cases of \{VAP\} than in other cases. Conclusions Observed incidence rates associated with \{VAP\} and CPAP-PNEU, were higher than in other national surveillance systems and expressing the feasibility of lowering the risk of LO-PNEU and increasing patient safety. The incidence of pneumonia was found to be lower when using \{CPAP\} as compared to using MV.