Although nasogastric tube (NGT) decompression is widely used in nonoperative management for adhesive small bowel obstruction (SBO), robust evidence is lacking to support this routine practice. Patients who received nonoperative management with a diagnosis of adhesive SBO were retrospectively reviewed. Those who received NGT or long-tube decompression at admission were categorized into the NGT group, while those who initially had no NGT placement were categorized into the non-NGT group. The incidence of vomiting after admission, pneumonia after admission, and the need for surgery were compared. Among 288 patients, 148 (51.3%) had non-NGT conservative treatment. There were no significant differences in the incidence of vomiting (NGT vs non-NGT: 12.9% vs 18.9%, p = 0.16), pneumonia (1.4% vs 0%, p = 0.235), or need for surgery (12.9% vs 7.4%, p = 0.126). While NGT decompression is a standard of care for adhesive SBO, selective NGT insertion for patients with persistent nausea or vomiting can become an option. •Vomiting rate was low in nonoperative management without nasogastric tube.•Non-nasogastric tube decompression did not increase pneumonia and need for surgery.•Non-nasogastric tube decompression did not increase vomiting rate in patients with large gastric volumes.•Selective patients may avoid nasogastric tube insertion in nonoperative management.