Purpose: Medication iatrogeny is a major public health problem that increases as the population ages. Therapeutic escalation to control pain and associated disorders could increase polypharmacy and iatrogeny. This study aimed to characterize the medication iatrogenic risk of elderly outpatients with chronic pain. Methods: This was a prospective cohort study recruiting patients 65 years or older with chronic pain. A medication iatrogenic assessment was performed based on the best possible medication history to record risk of adverse drug events (Trivalle score), STOPP (Screening Tool of Older Person's Prescriptions)/START (Screening Tool to Alert doctors to Right Treatment) criteria, and potentially inappropriate medications. Results: We recruited 100 patients with an average age of 71 years. The median number of medications before pain consultation was 8 (interquartile range = [7;11]). Trivalle score showed that 43% of patients were at moderate or high medication iatrogenic risk. Before consultation, 79% and 75% of patients had at least 1 STOPP or START criterion on their orders, respectively. One-third of orders mentioned benzodiazepine prescribed for more than 4 weeks. At least 1 potentially inappropriate medication was prescribed for 54% of the patients, with a median of 1 per patient (interquartile range = [0;1]). A combination of several anticholinergics was prescribed in 23% of patients. Conclusion: Elderly patients with chronic pain are at risk of medication iatrogeny. Preventive measures as multidisciplinary medication review could reduce the iatrogenic risk in these outpatients.This study is registered at clinicaltrials.gov as NCT04006444 on July 3, 2019.