Necrotizing enterocolitis (NEC) is the most common surgical disease in the neonatal period with a high mortality rate. To date, there is no consensus on the indications for surgery in the absence of pneumoperitoneum. This study aimed to determine the indications for surgery in pre-term infants with NEC and their mortality. We conducted a descriptive, observational, cross-sectional, and retrospective study including pre-term infants with NEC from two perinatal hospitals in Toluca, Mexico, between 2017 and 2022. Descriptive and inferential statistics and group comparisons were performed using Fisher and Kruskal-Wallis tests. Of 236 patients with NEC, 52 (22%) required surgery; we analyzed 42 cases with complete clinical records. The indications for surgery were divided into (a) clinical deterioration (33.3%); (b) radiographic findings (31%); (c) laboratory alterations (19%); and (d) positive paracentesis (16.7%). The group of radiographic findings underwent surgery later, up to 2 days after the other groups. The mortality rate of surgical NEC was 42.9%. The most common indication for surgery in pre-term infants with NEC was clinical worsening despite optimal medical management; radiographic findings were the indication associated with the highest mortality. Laboratory abnormalities and positive paracentesis were the indications with the best outcomes but the least used.