Chemotherapy and radiotherapy proved conservative and effective in treating tumors. However, both the cancer therapies will also have aberrant effects on developing maxillofacial and dental organs of children. The purpose of this report is to describe the clinical cases of Disturbances of maxillofacial and dental development after Cancer therapy. The first case reported a 7-year-old female patient diagnosed at age 2 years with bilateral retinoblastoma, receiving chemotherapy and radiotherapy. She had agenesis of premolar, microdontia, short tapered teeth in lower anterior area and generalized root stunting. The second case presented a 12-year-old female patient treated with chemotherapy and radiotherapy for neuroblastoma in her early childhood. She presented with a class III malocclusion on a skeletal III base due to maxillary retrognathism. Contemporay oncology had improved survival of children with malignant disease. It will be needed prevention of these side effect after cancer therapy to improve the quality of life.