OBJECTIVES: The objective of our study was to determine the predictive factors of their occurrence during conservative surgical treatment of the hepatic hydatid cyst (HHC). PATIENTS AND METHODS: We carried out a retrospective review of patients who had undergone conservative surgical treatment of the HHC during 6 years. Univariate analyzes were used to determine the predictive factors of an occult cystobiliary fistula (CBF). RESULTS: This current study included 105 patients. Concerning the predictive factors of an CBF regardless of its pattern of evolution, we noted that the presence of fistula was statistically correlated with the a cyst size (bigger than 8.65 cm ; p = 0.003) and with advanced age (p=0.035). Interestingly enough, the correlation to a degenerated cyst (p=0.069) were of little significance. CONCLUSION: The size of the cyst greater than 8.65 cm and the advanced age are the risk factors of CBF according to our study.