OBJECTIVES: The Rome III criteria define pediatric irritable bowel syndrome with constipation (IBS-C) as abdominal pain or discomfort associated with constipation symptoms.  Historically, few pediatric IBS-C trials have used symptom measures that were developed with patient input.  This study aimed to develop pediatric IBS-C symptom measures through qualitative interviews with children with IBS-C and their parents/caregivers. METHODS: Children diagnosed with IBS-C (aged 6–8 [n=10], 9–11 [n=10] and 12–17 [n=10]) and their parents were interviewed. Thematic analysis of interview transcripts identified concepts. Age appropriate items and response options, developed to measure each concept, were reviewed by expert clinicians. RESULTS: IBS-C symptoms identified as being bothersome to children included: abdominal symptoms such as abdominal pain (‘stomach hurts’) and bloating (‘tummy like a balloon’), and bowel symptoms such as infrequent bowel movements (‘don’t go often’), difficulty defecating (‘it won’t come out’), straining on defecation (‘have to push hard’), rectal pain during defecation (‘butt hurts’), hard stools (‘hard and bumpy’), large stools (‘it’s like a log’), and a feeling of incomplete evacuation (‘some that won’t come out’). Saturation was achieved for the above concepts.  Parents relied on behavioural signs of IBS-C (such as inactivity or irritability) and the child telling them about symptoms when assessing their child’s condition. In general the majority of parents and children agreed in their reports of symptoms, though there were some minor inconsistencies. CONCLUSIONS: Consistent with guidelines for patient-reported outcomes, these results were used to develop age-appropriate questions to measure both abdominal and bowel symptoms. The instrument is currently undergoing testing to assess patient understanding and relevance. Results from qualitative interviews with children with IBS-C suggest abdominal and bowel symptoms are both important and bothersome to pediatric IBS-C patients and should be included in treatment assessments.