Case Report: Patient JPVV, male gender, 18 years old, ASA 1, appeared in Oral Surgery department of FMUC on 27/06/14, referring diffuse pain in the upper jaw. After clinical examination, patient revealed vestibular swelling in region 11 and 12. After sensitivity tests, 11 showed negative response, consistent with necrotic pulp and 12 expressed no change. Diagnostic tests (Orthopantomography, apical X-ray and Cone-Beam) revealed the presence of a radiolucent unilocular and homogeneous lesion with well defined radiopaque edges at the level of the apical region of teeth 11 and 12. Treatment plan was, endodontic treatment of 11 associated with decompression and subsequent cystic enucleation. The pathologic results of incisional biopsy were consistent with an odontogenic radicular cyst. Periodic evaluations were made. Drain was removed 195 days after new Cone-Beam analysis, in which the almost complete regression of the lesion was observed. Patient is under surveillance, advancing to the surgery only if there is any recurrence. Discussion: Cystic decompression is a minimally invasive option, which through a decompressor system (drain) decreases intra-cystic pressure, promoting osteogenesis. It is a time consuming technique that requires high patient compliance. Conclusion: Cystic decompression is assumed as an alternative or a complement to a resective surgical technique, especially in cases of large lesions where immediate excision involve large bone destruction with possible impairment of noble anatomical structures. Keywords: odontogenic cysts, jaw cysts, cyst's treatment, cyst's decompression, enucleation