The main aim of the study was the determination of the content of selected metal ions in soils originating from Polesie Lubelskie and Biebrza River Region, as well as an attempt at relating the results obtained to the degree of secondary transformation of studied soils. All the soils belonged to peat-muck soils and differed from each other in their secondary transformation index. The study included analyses of the content of potassium, calcium, magnesium and manganese with the use of absorption atomic spectroscopy for the determination of the concentration of those metals. At the next stage of the study, relationships between the secondary transformation index of peat-muck soils and selected metal contents were examined. Weak linear relationships were found for the secondary transformation index and the content of calcium, manganese and potassium. A more complex situation was observed for the relation of magnesium ions. The lack of a straight-line trend could be explained in this case by the effect of chemical processes occurring in particular classes of mucks transformation on magnesium ion binding.