There is a wide range of malignant tumours with an embryonic origin that can affect children in their early childhood including Rhabdomyosarcoma, Osteosarcoma, Chloroma, Retinoblastoma and neuroblastoma. Different protocols have been developed over the past years to treat these tumours and different combinations of radiotherapy, surgery and chemotherapy were used. This improved the survival rate considerably. This treatment has a marked effect on growth of soft and hard tissues in the affected regions of the head and face, leading to facial and dental abnormalities that become evident with growth. The great effect of radiotherapy and chemotherapy on craniofacial skeletal growth should be considered in all cases undergoing treatment for tumours. The resulting dental and maxillofacial abnormalities should be expected in all cases and its management require involvement of different members of the medical team including maxillofacial surgeon, restorative dentist, orthodontist, psychologist, dietician, speech therapist, the patient and the parents in order to achieve maximum results. This paper presents four patients who underwent radiotherapy and chemotherapy for treatment of embryonic tumours and discusses the main side effects of the treatment.