AimThis prospective study evaluated the incidence of functional gastrointestinal disorders (FGIDs) during infancy, on their own or combined with other symptoms.MethodsWe asked 273 French paediatricians with a specific interest in FGIDs to provide feedback on 2757 infants aged zero to six months from March 2013 to January 2014. Gastrointestinal health status was assessed by two questionnaires at inclusion and at a four‐week follow‐up visit. FGIDs were assessed according to the Rome III criteria and quality of life (QoL) was monitored.ResultsCombined FGIDs were diagnosed in 2145 (78%) infants: 63% with two disorders and 15% with three or more disorders. The most frequently combined FGIDs were gas/bloating and colic (28%), colic and regurgitation (17.0%) and gas/bloating and regurgitation (8%). Compared to infants with a single FGID, combined FGID were associated with lower body weight (4.63 vs 4.79 kg, p = 0.009), shorter breastfeeding duration (33 vs 43 days, p < 0.001), a decreased QoL score (5.9 vs 6.5, p < 0.001), more frequent drug prescriptions (25% vs 13%, p < 0.001) and significantly greater improvements in QoL scores after four weeks (p = 0.003).ConclusionCombined FGIDs were extremely common in infants up to six months of age and had a negative impact on breastfeeding, weight gain and QoL.