This experiment was carried out in laboratory conditions. The aim of this work was estimating allelopathic potential of Taraxacum officinale on seeds germination and initial growth of Poa pratensis. In the experiment different concentration of soil’s and plant’s water solution obtained from common dandelion were employed. The inhibition of germination energy of Poa pratensis under the influence of plant extracts produced from roots and leaves of Taraxacum officinale was found. Germination availability was inhibited in a higher degree by extracts prepared from the leaves than the roots of Taraxacum officinale. Higher concentrations of all solutions of both the soil and the plant inhibited the length of seending of Poa pratensis.