Osteoma is a benign connective tissue tumor that is slow-growing & osteogenic in nature and is uncommon in the craniofacial bones. These tumor consists of well-differentiated compact or cancellous bone. It is characterised by the excessive formation of compact and/or cancellous bone.(1) Among jaw bones, osteomas are more frequent in the mandible.(3) Case report: A 30 year old female presented with an initially painless, slowly enlarging growth on the left posterior alveolar ridge of mandible since about 5 years and with difficulty in chewing food due to swelling recently as the enlarged growth present on the alveolar ridge area between second and third molar of left mandible as it interfered with chewing as well as talking. The growth was a 1.5*1 cms gingival mass that extended bucco-lingually across occlusal area of color similar to adjacent normal mucosa with well-defined margins. It was sessile, firm, non-febrile and non-tender with a lobulated surface. OPG revealed a radiopaque sclerotic, well-defined mass surrounding and masking the root outline of left mandibular third molar and extending in between second and third molar with displacement of third molar posteriorly. It had dense compact bone with bone trabeculae of mature bone and with little & paucicellular fibrous connective tissue stroma at the periphery & also with presence of Osteoid cells in the decalcified tissue section. Discussion: Osteoma was first described by Jaffe in 1935. It is a bone tumor that may be syndromic or non-syndromic in its occurrence. Non-syndromic peripheral osteomas are believed by most researchers to be reactive lesionssecondary to trauma or lesions due to chronic muscle pull.