OBJECTIVE: To detail common comorbidities and procedures performed to evaluate functional nausea in children. STUDY DESIGN: In total, 63 children age 7-18 years seen in a tertiary care pediatric clinic who met Rome IV criteria for functional nausea prospectively completed an Intake Questionnaire, the Pediatric and Parent-Proxy PROMIS-25 Profile v 2.0, the Pediatric and Parent-Proxy Pediatric Sleep Disturbance-Short Form 4a, and the COMPASS 31 orthostatic intolerance scale to assess comorbidities. Medical records were reviewed for diagnostic tests performed to evaluate nausea and for additional comorbidities. Summary statistics were used to determine the most common comorbidities and diagnostic yield of the procedures. Intraclass correlation coefficients assessed agreement between parent and child reports on the PROMIS scales. RESULTS: Patients with functional nausea experienced multisystem comorbidities. A majority reported abdominal pain, headache, orthostatic intolerance, fatigue, disturbed sleep, anxiety, constipation, allergies, and vomiting. Agreement between parent-proxy and child report of symptoms on PROMIS scales was good to excellent (intraclass correlation coefficients = .78-.83; all P < .001). Patients underwent extensive diagnostic testing: 96 endoscopic procedures, 199 radiologic tests, and 4 cholecystectomies. Most of the procedures were not diagnostically informative. CONCLUSIONS: Children with functional nausea have comorbidities outside the gastrointestinal tract that warrant evaluation. Gastrointestinal diagnostic tests were of low-yield in identifying a cause. Understanding the relationship with comorbidities may provide insight into etiologies for the nausea and define clinical phenotypes to better tailor care.