Functional gastrointestinal disorders are common and costly to the health-care system. Most specialist care is provided by a gastroenterologist, but only a minority of patients have improvement in symptoms. Although they have proven to be effective, psychological, behavioural, and dietary therapies are not provided routinely. We aimed to compare the outcome of gastroenterologist-only standard care with multidisciplinary care.In an open-label, single-centre, pragmatic trial, consecutive new referrals of eligible patients aged 18-80 years with Rome IV criteria-defined functional gastrointestinal disorders were randomly assigned (1:2) to receive gastroenterologist-only standard care or multidisciplinary clinic care. The multidisciplinary clinic included gastroenterologists, dietitians, gut-focused hypnotherapists, psychiatrists, and behavioural (biofeedback) physiotherapists. Randomisation was stratified by Rome IV disorder and whether referred from gastroenterology or colorectal clinic. Outcomes were assessed at clinic discharge or 9 months after the initial visit. The primary outcome was a score of 4 (slightly better) or 5 (much better) on a 5-point Likert scale assessing global symptom improvement. Modified intention-to-treat analysis included all patients who attended at least one clinic visit and who had answered the primary outcome question. This study is registered with ClinicalTrials.gov, NCT03078634.Between March 16, 2017, and May 10, 2018, 1632 patients referred to the hospital gastrointestinal clinics were screened, of whom 442 were eligible for a screening telephone call and 188 were randomly assigned to receive either standard care (n=65) or multidisciplinary care (n=123). 144 patients formed the modified intention-to-treat analysis (n=46 in the standard-care group and n=98 in the multidisciplinary-care group), 90 (63%) of whom were women. 61 (62%) of 98 patients in the multidisciplinary-care group patients saw allied clinicians. 26 (57%) patients in the standard-care group and 82 (84%) patients in the multidisciplinary-care group had global symptom improvement (risk ratio 1·50 [95% CI 1·13-1·93]; p=0·00045). 29 (63%) patients in the standard-care group and 81 (83%) patients in the multidisciplinary-care group had adequate relief of symptoms in the past 7 days (p=0·010). Patients in the multidisciplinary-care group were more likely to experience a 50% or higher reduction in all Gastrointestinal Symptom Severity Index symptom clusters than were patients in the standard-care group. Of the patients with irritable bowel syndrome, a 50-point or higher reduction in IBS-SSS occurred in 10 (38%) of 26 patients in the standard care group compared with 39 (66%) of 59 patients in the multidisciplinary-care group (p=0·017). Of the patients with functional dyspepsia, a 50% reduction in the Nepean Dyspepsia Index was noted in three (11%) of 11 patients in the standard-care group and in 13 (46%) of 28 in the multidisciplinary-care group (p=0·47). After treatment, the median HADS scores were higher in the standard-care group than in the multidisciplinary-care group (13 [8-20] vs 10 [6-16]; p=0·096) and the median EQ-5D-5L quality of life visual analogue scale was lower in the standard-care group compared with the multidisciplinary-care group (70 [IQR 50-80] vs 75 [65-85]; p=0·0087). The eight SF-36 scales did not differ between the groups at discharge. After treatment, median Somatic Symptom Scale-8 score was higher in the standard-care group than in the multidisciplinary-care group (10 [IQR 7-7] vs 9 [5-13]; p=0·082). Cost per successful outcome was higher in the standard-care group than the multidisciplinary-care group.Integrated multidisciplinary clinical care appears to be superior to gastroenterologist-only care in relation to symptoms, specific functional disorders, psychological state, quality of life, and cost of care for the treatment of functional gastrointestinal disorders. Consideration should be given to providing multidisciplinary care for patients with a functional gastrointestinal disorder.None.