Humic substances form most of the organic component of soil, peat and natural waters, but their structure and properties very much differs depending on their source. The aim of this study is to characterize humic acids from raised bog peat to evaluate the homogeneity of humic acids isolated from the bog bodies and study peat humification impact on properties of humic acids. Peat humic acids (HA) have an intermediate position between the living organic matter and coal organic matter.