More than one-fifth of patients in neonatal intensive care units (NICUs) have been reported to suffer from healthcare-associated infections (HAIs). The aim of this study was to assess prevalence, onset and types of HAI in Finnish NICU patients. We conducted six monthly point-prevalence surveys in all Finnish NICUs (N=24) between November 2008 and May 2009. For all patients present on the day of survey, the underlying conditions and invasive devices or treatments used on the day of survey and during the preceding six days were recorded on standardised forms. All HAIs active or under treatment on the day of survey were included. HAIs were categorised into early-onset (onset within the first 72 h of life) and late-onset (onset after the first 72 h of life) infections. During the six surveys, 1281 forms were obtained. Among them, 164 HAIs in 163 patients were identified (overall prevalence, 13%); 63 (38%) of the HAIs were late-onset infections (prevalence, 6.5%). Main types of HAI were clinical sepsis, laboratory-confirmed bloodstream infection, conjunctivitis, and pneumonia. Of all HAIs, 24% were microbiologically confirmed. Patients with birth weight <1500 g suffered from late-onset HAIs more commonly than those with birth weight > or =1500 g (10% vs 4%, P<0.01). Also hospitalisation of > or =7 days was associated with increased prevalence of HAI (8% vs 3%, P=0.01). The study was useful in terms of increasing awareness of HAI in the participating NICUs. These results can be used to strengthen incidence surveillance of HAIs in the Finnish NICUs in the future.