Abstract: In this paper, relationships between metamorphism and chemical composition of garnets, taken fromregional metamorphic rocks surrounding Kırşehir Region are investigated.Investigation of metapelite and micaceous quartzite samples taken from three metamorphic zones in which metamorphic grade increases northward and northeastward, shows that MnO content of garnets decreases along thesame directions. MnO content of 29,23% of first metamorphic zone, turns out to be 12,81% in the second and finallybecomes 1% in the third zone.There is an apparent positive correlation between the modal content of garnets in metamorphic rocks and theMn-eontent of these minerals. It is found that garnets high in Mn-content appear to be less frequent and found inthe form of minute crystals whereas in the garnets low in Mn-content, the situation is reversed. Therefore it maybe argued that Mn-content of the original rock has been concentrated in occasional garnet crystals leading thismineral to be rich in Mn-content. However, chemical analyses of all garnet bearing rocks have shown that theyhave aproximately similar composition. Therefore this question arises: what were the conditions controllingnucleation and crystal growth of garnets starting from rocks with a similar Mn-content.As a result of this research it is found that estimation of physical conditions of metamorphism can not be donequantitatively by using composition of garnets nor through quantitative comparison of metamorphic conditions belonging to various metamorphic regions. However, existance of rather general relationship between increasing metamorphic grade and decreasing Mn-content of garnets from rocks of rather similar composition may be ruled out.