Various treatment methods for huge cystic lesion of the jaw exist, such as, resection of the involved bone, enucleation and decompression. Among these methods, enucleation after decompression is a conservative technique that decreases the size of the cystic cavity and reduces the risk of intrabony defects, which could be induced by primary enucleation. In addition, it can save the adjacent anatomic structures. In these cases, the decompression combined with partial enucleation, which was performed before complete cyst enucleation was performed on huge cystic lesions of the mandible. During the process, a decrease in the size of the lesion and the growth of normal oral tissues was observed. The size of the lesion decreased until the time of complete enucleation, and surgery could be performed under local anesthesia. No damage to inferior alveolar nerve was observed. We report these cases with a review of the relevant literature.