AIMS AND OBJECTIVES:This study aimed to determine the prevalence, severity, location and duration of pain post-colonoscopy, and to explore possible associations between pain, demographic variables and diagnostic findings. The study also sought to provide information to guide decision-making on CO2 insufflation. BACKGROUND:Colonoscopy with sedation is a common day surgery procedure in Australia. Attendance for colonoscopy is influenced by patient expectations, particularly about pain. Research on post-colonoscopy pain has focussed on pain experienced immediately post-procedure, with few studies investigating pain beyond 24 hours. DESIGN:Follow-up study using patient-completed Pain Numerical Rating Scales. METHODS:Patients undergoing colonoscopy at a single hospital day surgery unit were invited to complete Pain Numerical Rating Scales (where 0 = no pain and 10 = worst possible pain) three times daily for three days post-colonoscopy. RESULTS:Among the 277 participants, 124 (45%) reported pain at any time during follow-up. Twenty-one (8%) participants experienced pain on each of the three days. Pain was most commonly experienced in the hypogastric and iliac regions. The severity of pain was low, with only 33 participants self-administering analgesics (paracetamol or nonsteroidal anti-inflammatory drugs) during follow-up. Participants who had both colonoscopy and gastroscopy were not more likely to report pain overall. However, they were more likely to report pain on days 2 and 3 and were also more likely to take analgesics. Pain was not associated with procedure duration, abdominal pressurisation, removal of polyps, diverticulitis, inflammatory bowel disease or the presence of benign or malignant lesions. CONCLUSIONS:This research indicates that fewer than half of the patients undergoing colonoscopy will experience post-procedure pain and that just over one in ten patients will require analgesics. Patients undergoing both gastroscopy and colonoscopy are more likely to experience pain for longer and require over-the-counter analgesics. The low prevalence of pain suggests that room air insufflation is an acceptable alternative to more expensive CO2 . RELEVANCE TO CLINICAL PRACTICE:The findings provide evidence for nurses and clinicians to advise patients about the likelihood of experiencing pain post-colonoscopy, and the characteristics of this pain. Nurses may reassure patients that pain is not more likely among patients diagnosed with colorectal disease or malignancy. Patients who have persistent pain for longer than 24 hours post-colonoscopy should be advised to seek medical care to investigate the cause of their pain.