OBJECTIVES: Irritable Bowel Syndrome (IBS) is a chronic and relapsing sickness of high economic impact on society and patients’ life quality. The purpose of this study is to estimate the cost-effectiveness of treatment with otilonium bromide (OB) compared with pinaverium bromide (PB) and hyoscine butilbromide (HB) in the treatment of abdominal pain in patients with IBS from an institutional perspective. METHODS: A cost-effectiveness analysis was developed using a Markov modeling approach: The model simulates cost and effectiveness outcomes in a 6 month period for treatment of IBS with OB (40mg every 8 hrs); PB (10-20mg every 8 hrs); and HB (50mg every 8 hrs). Three health conditions were considered (“symptom control”, “continuing symptom profile” and “relapse”) with a 7-day cycles. Effectiveness measures: clinic success rate and symptomless time. The probabilities of transition were estimated from international random clinical. Costs and resource use were collected from hospital records related to patients with IBS at IMSS in 2010 (n=150). The probabilistic sensitivity analysis was obtained through a second-order Monte Carlo simulation RESULTS: The greatest effectiveness of clinic improvement was shown by patients treated with OB (76%) followed by those of PB (72%) and HB (66%). The greatest effectiveness in symptomless conditions was shown by OB (18 weeks) followed PB (17 weeks) and HB (15 weeks). Thus, mean cost per patient were lower with OB (US$ 505.22) followed by PB (US$530.74) and HB (US$642.71). Regarding the ICER, OB resulted the dominant therapy. Acceptability curves showed OB as the most cost-effective therapy in 100% independently of IMSS willingness to pay. CONCLUSIONS: In Mexico, OB represents the best cost-effective alternative since it offers greater control and more symptomless weeks in patients with IBS. These results should be taken into account by Mexican decision makers