© 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Aim: We aimed to determine predictive factors for predicting cystobiliary fistulas (CBF) in children after treatment of liver hydatid cyst (LHD). Methods: The records of patients who were treated for LHD between 01.06.2009 and 1.06.2019 were retrospectively reviewed. Age, sex, laboratory test results, size and number of cysts, method of first intervention (percutaneous or surgery), whether or not CBF developed and how it was treated were investigated. Among findings, those could be predictive were investigated. Data were evaluated with SPSS 21.0 program, p < 0.05 was considered significant. Results: Of the 97 patients, 48 (49.5%) were male, 49 (50.5%) female, the mean age was 11.2 years, Eighty patients had right (82.5%), 13 had left, and 4 had bilobar involvement. As first intervention, surgery was performed in 39 (40.2%); percutaneous treatment was performed in 58 (59.8%) patients. In 8 patients (20.5%) in surgery group and in 6 patients (10.3%) in percutaneous group, totally in 14 patients (14.4%), CBF developed. The mean cyst diameter of CBF-developed group was 114.36 mm, and of CBF-undeveloped group was 74.30 mm. There was no statistically significant differences between groups in terms of age, sex, involved lobe, other organ involvement, and preoperative results (p > 0.5). There was a significant relationship between the cyst diameter and the rate of CBF development in both surgical and percutaneous groups (p < 0.05). ROC analysis was performed, and the cut-off value for the development of CBF detected as 69 mm for children. Since obstructive jaundice seen in adults is not common in children, an increase in liver function tests and bilirubin levels were not seen in our patients. Conclusion: A significant correlation was found only between the size of the cyst and developing CBF. Cysts greater than 69 mm have a higher risk of developing CBF after both percutaneous and surgical treatment and should be closely monitored.