OBJECTIVES: Opioid-induced constipation (OIC) is the most common and distressing side effect of opioid treatment in patients with chronic pain. There are limited data to estimate the occurrence of OIC; however, estimates in non-cancer patients range from 40-50% and can be as high as 90% in cancer patients. Increased resource utilisation is associated with the diagnosis and management of OIC; however, the economic burden of OIC remains under-reported. METHODS: This review considered the cost of illness associated with OIC. A targeted literature review was conducted for all publications since 2000 that evaluated the economic burden of OIC. Databases used for the literature search were PubMed, Embase, and HEED. All costs were converted to a 2014 USD cost base. RESULTS: Eleven studies were identified which reported direct healthcare costs associated with OIC. All studies reported increased direct costs related to OIC; however, estimates per country varied significantly. Direct healthcare costs specifically related to OIC ranged from $1,747 to $48,782 per patient year. Per patient episode, direct costs associated with OIC ranged from $54 to $11,705. This was further supported by a large international study which reported significantly more physician visits and alternative care provider visits among patients with OIC than those without OIC. Two studies reported on a subgroup of patients with OIC who failed to respond to laxatives; these patients reported higher direct costs than patients who had a response to laxatives. CONCLUSIONS: The management of OIC is associated with potentially significant healthcare resource utilisation and financial burden. Patients with OIC incur higher direct healthcare costs than those without OIC and costs are increased further if patients with OIC have failed to respond to laxatives. There remains a paucity of data on healthcare resource utilisation in OIC and further research into the economic burden of OIC is needed.