Background: Obstructive ileus is a gastrointestinal emergency caused by mechanical obstruction of the intestinal tract and may require surgical intervention. Acute postoperative pain is one of the common problems following laparotomy and may interfere with comfort, mobility, and recovery. Purpose: To describe comprehensive nursing care for a child following laparotomy for obstructive ileus with acute pain as the primary nursing diagnosis and to describe the application of deep breathing relaxation as a complementary intervention for pain management. Method: This study used a descriptive case study approach. Data were collected through interviews, observation, physical examination, documentation, and medical record review. Nursing care was developed according to the Indonesian Nursing Diagnosis Standards (SDKI), Indonesian Nursing Outcome Standards (SLKI), and Indonesian Nursing Intervention Standards (SIKI). Results: The patient was a 9-year-old boy who reported postoperative pain with an intensity of 5 on the Numeric Rating Scale (NRS). The patient demonstrated grimacing, protective behavior toward the surgical wound, and anxiety during movement. After three days of nursing care combining pharmacological therapy and deep breathing relaxation, pain intensity decreased from 5 to 4. The patient appeared more relaxed, showed reduced grimacing and protective behavior, and was able to perform the deep breathing relaxation technique independently. Conclusion: Deep breathing relaxation provided positive complementary effects in managing acute postoperative pain in this pediatric patient. Although pain was not completely resolved, the intervention was associated with reduced pain intensity and improved behavioral responses and pain-control ability.