In September 2019, the Bourgogne-Franche-Comté Regional Health Agency asked Santé publique France to investigate a suspected cluster of pediatric cancers in the Jura region, as reported by parents of affected children. To validate the spatio-temporal clustering, the method employed involved a retrospective search to determine whether an excess of pediatric cancers was observed in a defined geographic area, compared to cancer rates observed in mainland France. Analyses were conducted for all cancers and for leukemias, the most common cancer in children. The investigation involved 13 children under the age of 15 and 4 over the age of 15 at the time of diagnosis between 2010 and 2020 (including 7 cases of leukemia). An excess of “all cancers” and an excess of leukemia were identified in a cluster of municipalities comprising 3 catchment areas. An epidemiological study was conducted using a questionnaire administered to parents, and an environmental assessment was performed to examine known environmental risk factors. This study did not aim to identify individual causes for each cancer but rather to identify a common factor among the children, specific to the geographic area, that could explain the cluster of cases. The investigations did not identify any common factor among the affected children, and the environmental assessment did not reveal any anomalies. In the absence of an etiological hypothesis, conducting a specific environmental monitoring campaign was not warranted. Consequently, in the absence of an identified cause, the hypothesis of a one-time cluster of cases must be verified. Santé publique France recommends continuing to monitor the incidence of pediatric cancers in the study area for several years to track changes in the incidence of these diseases.