Objectives: The aim of the research is to determine the concentrations of calcium, phosphorus and their interrelationship in samples of primary and permanent teeth affected by caries. Material and methods: The study was conducted on teeth collected at a dental clinic. Collected teeth are primary teeth and permanent teeth affected by caries. Calcium concentration was determined by flame absorption spectrometry (FAAS) on an atomic absorption spectrometer AnalytikJena AG, model AAS Vario 6. Phosphorus concentration was determined by UV VIS spectrophotometry, on a UV VIS spectrophotometer Perkin Elmer Lambda 25, double beam. Results: The study was conducted on 20 teeth: 10 deciduous and 10 permanent (karyotic) teeth. The mean value of calcium in primary teeth is 26.372%, and the mean value of calcium in samples of permanent teeth is 24.597%. The mean value of phosphorus in primary teeth is 11.785% and the mean value of phosphorus in permanent teeth is 14.115%. The Ca / P ratio is 2.277 in primary teeth and the Ca / P ratio in permanent teeth is 1.748. Conclusion: The study found that the concentration of calcium is lower in samples of permanent (karyotic) teeth, the concentration of phosphorus is higher in samples of permanent (karyotic) teeth and that the Ca / P ratio is lower in samples of permanent (karyotic) teeth compared to primary teeth. The obtained results indicate the need for further research since there is not a large number of studies on this topic.