Introduction: Functional gastrointestinal disorders (FGIDs) are a very common pediatric disease, with strong implications for children and their families. We aimed to determine their frequency in our environment (per Rome IV criteria) and to establish if there is seasonal variability in diagnosis. Material and methods: Descriptive, prospective study. For 12 months, children under 16 years of age with suspected FGIDs who had a first pediatric gastroenterology consultation were included and classified according to Rome IV criteria. Statistical analysis was done with SPSS v22. Results: 574 children received consultations, 67% were >4 years of age. FGIDs were suspected in 44.6% of the patients, 32.4% were diagnosed according to Rome IV criteria (16.4%, <4 years; 40.3%, >4 years). 51.1% were female, average age of 8.4 +/- 4.2 years and mean of 7 months of symptoms until diagnosis (range 3-150). In patients <4 years, the most common disorders were functional constipation (48.4%), regurgitation (22.5%) and functional diarrhea (16.1%); in patients >4 years of age, functional abdominal pain (29%), functional dyspepsia (28.4%) and functional constipation (16.8%) were most frequent. We did not discern seasonal variations in diagnosis in the global study population (p=.96) or by age group (< 4, P=.51; > 4, P=.57). Conclusions: FGIDs account for one third of our patients' consultations. While the Rome IV criteria are more inclusive than before, almost 30% of patients with suspected FGIDs do not meet said criteria. Although a seasonal difference regarding diagnosis was observed, it was not statistically significant either in the sample group as a whole or by age group. (c) 2021 Asociacion Espanola de Pediatria. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).