: Purpose: Children with medical complexity experience frequent pain. But it can be challenging to recognize unexpected behaviors as pain related, especially in the absence of self-report. Often these children undergo extensive workups aimed at diagnosing the sources of pain. This study had three objectives: to describe the signs and symptoms parents of nonverbal children with medical complexity found worrisome, to describe the sources of pain in these children, and to describe nursing pain assessment practices in this population. DESIGN AND METHODS: Retrospective chart review was used to identify the initial presenting symptoms, sources of pain, and nursing documentation for 46 children with medical complexity who were admitted with a chief concern of pain to a 395-bed pediatric teaching hospital in the northeastern United States. RESULTS: Irritability, pain, feeding intolerance, and "not acting like herself [or himself]" were common parent-reported symptoms that prompted further evaluation. On average, five diagnostic studies were taken to identify a source of pain, and four specialty services were consulted during the admission. Nursing assessments of pain were documented approximately every three hours; the mean pain intensity score documented was 1.1 out of 10. The discharge diagnoses included infection (including urinary tract infection), seizures, constipation, chronic pain, failure to thrive, dehydration, and subdural hematoma. CONCLUSIONS: The discharge diagnoses covered a wide range. A systematic approach to pain evaluation could help to ensure that the diagnostic process is both thorough and efficient. Common childhood ailments such as constipation or urinary tract infection, as well as other causes, must be considered when diagnosing pain in this population. Practice implications include consulting parents regarding changes in a child’s behavior.