Primary peritoneal drainage (PPD) was initially introduced as a method for the pre-operative resuscitation of critically ill infants with complicated necrotising enterocolitis (NEC). Some have recommended it as definitive strategy for a select group of extremely low birth weight babies. The role of laparotomy in neonates who do not respond to initial PPD has also been challenged. With this background, we analysed our experience with the use of PPD in babies with NEC over an 18-year period. We retrospectively reviewed all patients with NEC who had PPD as their initial surgical management over an 18-year period. A total of 122 babies with NEC were treated surgically, of whom 42 had PPD as the initial procedure. There were 28 survivors (67%) in the PPD group, of whom 7 recovered without laparotomy. Twenty-nine infants (69%) had a good clinical response to PPD with 80% (23/29) survival, compared to a 27% survival (3/11) in those who did not respond to drainage. Six patients underwent rescue laparotomy after a poor response to PPD and three of these survived. Six of the 28 pts who underwent laparotomy had isolated intestinal perforation and their clinical characteristics were no different from those with typical NEC. PPD is a useful option in the management of complicated NEC. It is difficult to recognise with certainty those infants who will not require a subsequent laparotomy and therefore we do not support the concept of PPD solely as a definitive strategy. The response to PPD is a good prognostic indicator for ultimate survival. Despite a low salvage rate of 27% in non-responders compared to 80% in responders, there is a role for early laparotomy for those infants who do not respond to PPD.