The objective of this work was to investigate the wood volume density and fiber length of wood of some poplar clones aged 10 years, obtained at Institute of Lowland Forestry and Environment in Novi Sad. For chemical composition of wood samples were taken from different height of stem and regarding to standard analyses of main chemical constituent of cell wail wood tissue: cellulose, lignin, and pentozanes, as well as extractives and ash content. Variability of chemical composition was determined by statistical methods. There are significant differences between the contents of all individual components of wood chemical composition.