Introduction: Irritable bowel syndrome (IBS) has substantial impact on Quality of Life (QoL) and patients have high healthcare utilization. Guidelines recommend diagnosis and management within primary care, yet around 25% of patients are referred to gastroenterology. These studies aimed to assess the incidence of organic gastrointestinal disease in patients diagnosed with IBS, the cost of healthcare utilization and the QoL in patients with IBS before and after seeing a gastroenterologist and to estimate the cost-effectiveness of a gastroenterology appointment. Methods: Patients with IBS were identified within the UK Clinical Practice Research Dataset. Incidence rates of coeliac disease, colorectal cancer (CRC) and inflammatory bowel disease (IBD) were calculated. Individual-level healthcare utilization data were extracted for IBS patients who first visited a gastroenterologist in 2008 or 2009. Mean costs of total healthcare utilization were calculated before and after gastroenterology attendance. A questionnaire study of patients with IBS attending a gastroenterology outpatient clinic for the first time measured QoL and utility before and after the appointment. Quality Adjusted Life Years (QALYs) were modeled from these utility values. Cost-effectiveness of a referral to gastroenterology in IBS was assessed using mean cost per QALY. Results: Fifteen years after IBS diagnosis, the combined cumulative excess incidence of coeliac disease, IBD and CRC in IBS is 3.7%. Over one year following gastroenterology appointment, the expected QALY gain compared to no appointment was 0.03 and the expected extra total healthcare costs were £657. The incremental cost-effectiveness ratio was £27865.64/QALY. Referral for patients younger than 30, men, and increasing the time horizon, reduces the expected cost effectiveness. Conclusions: My findings provide reassurance that non-specialists are unlikely to be missing an organic condition in the majority of IBS patients. Referral to a gastroenterologist for IBS might be cost-effective for the NHS but more data, especially on potential QALY gains, are needed.