This paper reports a microdiffusion method using fluoride-ion selective electrode for determination of fluoride contents in dietary samples. The method was suitable for the determination of fluoride in different dietary samples. It was a simple and fast method, and could be applied in large amount of sample analysis. The minimum detectable limit of this method was 1.0 microgram fluoride in 1.0 g dry dietary sample. The range of fluoride recovery and RSD in this dietary samples were 85.0%-107.0% and 4.5%-9.5% respectively. The fluoride content determined in the oyster tissue of NBS 1566 SRM was 87.9%-104.6% of certified SRM, and RSD was 6.5%. The RSD of fluoride determination in alcohol drinks was 3.1%.