The water supply of Canberra was fluoridated in eptember 1964. This report covers the period 1965 to 1974 during which children aged five to twelve years were examined. These children had lived in Canberra since fluoridation commenced. In comparison with base-line data the results showed a progressive improvement in the DMF and defindices. The reduction in the DMF index for children aged six years who were examined in 1974 was 81.0 per cent, and for children aged twelve years it was 48.5 per cent. The reduction was greatest for incisor teeth.