Mixed odontogenic tumors in the jaws of children and adolescents usually cause dentition anomalies. The typical forms of these are ameloblastic fibroma, ameloblastic fibroodontoma, complex odontoma and compound odontoma. In the present study mixed odontogenic tumor cases are presented in patients under 20 years of age. All of them were associated with tooth eruption disturbances. Further aim of this study was to discuss the nature and interrelationships of this group of lesions. Ameloblastic fibromas (AFs) are true, mixed, soft tissue neoplasms, deriving from the proliferation of both odontogenic epithelium and mesenchyma. They have a potential to both recurrence and malignant transformation. Ameloblastic fibroodontomas (AFOs) may be regarded as hamartomas, which exhibit epithelial, mesenchymal and abundant hard tissue components of the developing teeth. Odontomas are calcifying benign hamartomas, and represent the most common type of odontogenic jaw tumors among patients less than 20y, having complex and compound variants. Complex odontomas (CXOs) are built up from amorphous hard tissue elements, and generally occur in the premolar or molar regions of the maxilla. Compound odontomas (CDOs) usually appear in the maxilla, in the region of the incisors and canines, and contain small, radio-opaque structures reminiscent of rudimentary teeth. Early diagnosis and treatment of mixed odontogenic jaw tumors in children may prevent the serious orthodontic complications and jaw deformations.