A foreign body impacted in the esophagus could be a sign of eosinophilic esophagitis (EoE). Our aim was to investigate if children previously diagnosed with a foreign body in the esophagus had a missed diagnosis of EoE. In this population-based longitudinal study, all children (0-18 years) diagnosed with a foreign body in the esophagus in Stockholm, Sweden 2006 to 2016, were identified. In addition to a review of medical files, each family was contacted (n = 325) and asked standardized questions. Children with symptoms indicating EoE were offered esophagogastroduodenoscopy (EGD). We found 325 pediatric cases of foreign body. Two hundred and seven (64%) underwent an endoscopy at the event, 3 of these had biopsies taken, whereby 2 were diagnosed with EoE. Six additional patients were diagnosed with EoE between the initial event and the study follow-up. Children with persisting symptoms suggestive of EoE at the follow-up (n = 21), were offered EGD whereof 7 accepted. Four new cases of EoE were found. Hence, 12 (3.7%) of the children with a previous foreign body, either spontaneously released or endoscopically removed, were diagnosed with EoE. In the structured interview, dysphagia, food impactions and drinking excessively with meals, as well as food allergies, were significantly more common in EoE patients. Children with a foreign body in the esophagus are at risk of having EoE. Biopsies should be taken during foreign body removal and questions about swallowing problems and allergic diseases should be carefully explored also in children who do not need EGD because of spontaneous release.