Relative dating of archaeological bones by the measurement of fluorine, uranium, and nitrogen content (FUN method) is a well-established method. In this study, bone samples of Salt Men mummies of Chehrabad salt mine of Zanjan, IRAN, were relatively dated on the basis of FUN method. The amount of fluorine in the selected samples was measured by UV-Vis spectrophotometry, while the amount of uranium and nitrogen was determined by ICP-MS, and CHNS and Kjeldahl techniques, respectively. The results obtained suggest that firstly, corpse no. 3, then corpse no. 5, and finally corpse no. 2 have been buried. Comparing results obtained from FUN tests with radiocarbon ages of the samples showed that this methode could adequetly determined the sequence of the archaeological bones and their burial times. Moreover, this study revealed the high accuracy and precision of FUN relative dating test in the archaeological sites such as salt mines, where the samples are well-preserved, and also showed suitable consistent of the results obtained with the results of radiocarbon dating method.