It is rarely reported that primary femoral hydatid disease results from a dog bite wound contaminated by E. granulosus eggs. However, in this case, the primary femoral hydatid disease might occur due to a wound contaminated by E. granulosus eggs after the woman was bitten by her neighbor's dog 24 years earlier. The case of a 57-year-old woman suffering from primary osseous hydatid disease in the femoral condyle is presented here. Obtaining the correct diagnosis was difficult. A diagnosis of Echinococcus granulosus infestation was made histologically. The femoral osseous hydatid disease was treated by curettage and lavage with hypertonic salt for 10 minutes during surgery. After surgery, albendazole was administered to prevent recurrence (14 mg/kg/d for 6 weeks). The patient was recurrence-free after one year of follow-up. Our experience with this case is helpful. Human E. granulosus infection usually occurs after ingestion of food or water contaminated by E. granulosus eggs. It is more common from E. granulosus-contaminated food than from an E. granulosus-contaminated wound. Based on the evidence, we deduced that the primary bone hydatid disease did not result from ingestion of E. granulosus-contaminated food or water but instead from an E. granulosus-contaminated wound. Therefore, we hope that more clinicians will be able to verify this deduction by clinical observation or by carefully planned animal experiments.