Brief resolved unexplained event (BRUE) are transient and worrying episodes observed in infants and are characterized by changes in skin color, breathing, muscle tone, and/or responsiveness. We describe the case of a female infant who was initially diagnosed with BRUE but was later determined to have intussusception. She presented to our emergency department with a transient pallor and a single episode of vomiting that resolved before her visit. Physicians did not detect any abnormalities on physical or laboratory examinations, so she was diagnosed with BRUE and discharged to be re-evaluated the next day. After returning home, she vomited several times. The patient revisited our hospital the following day and was definitively diagnosed with intussusception using ultrasonography, which was successfully treated using fluoroscopy-guided hydrostatic reduction. This case was initially diagnosed as a BRUE; however, re-evaluation helped in identifying the proper diagnosis of intussusception. Physicians should exercise caution when diagnosing patients with BRUE. When the diagnostic criteria are not completely met, follow-up should be conducted, assuming that the patient has a potentially serious condition.