Many studies have reported that Acute Lymphoid Leukemia (ALL) is the most common type of cancer in children. The annual incidence of ALL in the Egyptian population was found to be 4 in every 100,000 children. The increase of childhood cancer survivors has allowed to investigate the long-term effects of cancer treatment. Researches have linked chemotherapy to some dental abnormalities including teeth hypodontia, microdontia, enamel defects, root disturbances and altered dental age as well as developing of new carious lesions. Accordingly, the aim of this study was to investigate the long-term effects of chemotherapy on the development of permanent dentition in patients who were treated from ALL.This cross section study was performed on 94 ALL survivors ranging from 6-18 years old who attended Children Cancer Hospital 57357, Egypt. Patients were diagnosed as Low-risk or Standard-risk patients according to protocol XV for ALL patients (Pui et al., 2000). All patients havefinished their programmed chemotherapy treatment before commencement of the study. In an attempt to correlate any dental abnormalities found in the study subjects to chemotherapy, a control group of age-matched 24 healthy individuals were enrolled from the orthodontic department, Cairo University, Egypt.Study groups were clinically examined for the presence or absence of missing teeth, microdontia, malformed teeth, enamel defects and supernumerary teeth. In addition to clinical examination, panoramic radiographs of the study groups were analysed for dental age assessment using a modified Demirjian’s method, Holtta defect index (DeI), abnormal root shapes, absence of teeth and missing roots.Dental abnormalities including (tooth agenesis, microdontia, Root/ Crown ratio, enamel defects or missing) showed no statistically significant difference between the study and the control groups except for the lowered Root/Crown ratio in the study sample. This could be clinically translated into grade I mobility of the affected teeth, however this was not statistically significant. Using the dental age estimation, no statistically significant difference was found between the dental age and chronological age in both groups. Dental defects calculated using DeI were statistically significant in the study group.