Introduction. Keratocystic odontogenic tumors (KCOT) or odontogenic keratocysts are aggressive and expansive odontogenic neoplasms with high recurrence rate (25%- 60%). There are a small number of publications about the combination of marsupialization and enucleation with the use of Carnoy's solution for the treatment of KCOT. Case report. In a female patient, aged 24, marsupialization KCOT was done in the first stage, and enucleation with the use of Carnoy's solution in the second stage, six months later. Lost sensibility of the lower lip was reestablished after three months. A postoperation defect was completely filled in seven months. One year later orthopantomographic x-ray showed the presence of a newly formed bone tissue, whereas in 7 years a completely preserved new mandibular bone and recanalisation of mandibular canal were observed. Conclusion. We consider that our method was successful in the treatment of KCOT, with no occurrence of recidives seven years later. However, it is necessary to follow the patient periodically because of a possible late recidive.