This paper describes the variation in neonatal nosocomial infection rates across 26 contributing units of the Australian and New Zealand Neonatal Network. Data collected during the years 2002–2004 have been analysed comprising a total of 3180 infants of <1000g birthweight and 260694 hospital-days. Overall infection rates of 5.02 [95% confidence interval (CI): 4.75, 5.30] infections per 1000 days total admission for infants of <1000g birthweight are comparable with other published data. Censoring data to the first 35 days of admission demonstrated an infection rate of 13.88 (95% CI: 13.14, 14.65) infections per 1000 days. A standardised, expected, infection rate for each unit was calculated by correcting for gestational age and gender. Analysis of the difference between observed and expected infection rates demonstrated considerable variation in nosocomial infection rates between participating units. Three units demonstrated a nosocomial infection rate significantly (P<0.005) below the population value. Further analysis of clinical practice variations within these units may uncover potential beneficial practices for the network.