Spontaneous intestinal perforation (SIP) in the newborn, also known as focal, idiopathic, or isolated intestinal perforation, typically affects extremely low birth weight (ELBW; <1000 g) or very low birth weight (VLBW; <1500 g) premature babies. The perforation is most often located in the terminal ileum.1 SIP can be difficult to distinguish from necrotizing enterocolitis (NEC), even though it is a separate clinical and pathological entity. If an infant with intestinal perforation is successfully treated by peritoneal drainage rather than primary laparotomy, the diagnosis of SIP is presumed rather than confirmed, and this has hindered interpretation of the literature. Reassuringly, however, in a large multicenter prospective study from the United States, 95% of babies undergoing laparotomy for presumed NEC or SIP were found to be correctly classified.2