Background: Survival following childhood cancer has increased considerably. We examined associations of specific types of cancer therapy with the presence of oral and dental abnormalities among childhood cancer survivors. Procedure: 131 children who were diagnosed with malignancies during childhood were referred to full oro-dental exams. Permanent teeth were examined clinically and radiographically to identify dental caries and anomalies in dental developmental: hypocalcification or hypoplasia, microdontia, root changes and absent tooth bud categorized hypodontia. Results: Dental developmental anomalies were observed in 56 (46%) of 121 children, in 309 teeth (9%). Hypocalcification or hypoplasia of enamel appeared in 21 (17%) patients. The mean decayed, missing and filled teeth (DMFT) score was 6.69 (SD 6.19). Altered root development appeared in 26 patients and hypodontia affected 13 (10%). Dental anomalies were observed in 36 (43%) individuals who received chemotherapy and not radiation, in 20 (52.63%) who received radiotherapy, and in 15 (60%) of those who received head & neck radiotherapy. Young age (under 6 years) was associated with a higher number of malformed teeth among patients who received only chemotherapy. Various chemotherapy agents associated similarly with dental anomalies and also with DMFT. Conclusions: Antineoplastic treatment that combines chemotherapy and radiotherapy appears to increase the risk of developing serious dental anomalies. Radiation to the head and neck area particularly increases the risk of dental developmental anomaly. No specific chemotherapy agent was found to be associated more than the others with dental side effects.