The purpose of the investigations was to determine the acute toxicity of some plant protection products for earthworms. The methodical bases of the studies were OECD Guideline No 207 and Good Laboratory Practice (GLP). The test species was Eisenia fetida (Sav.). The tested preparations were introduced into artificial soil in concentrations of 62.5; 125, 250, 500 and 1000 mg·kg⁻¹ dry matter of soil. The test duration was 14 days. The animals were weighed following that time and alive animals were counted and observed. Taking into account the obtained results, the values of toxicity of pesticides: LC₀ (the highest concentration of the test substance causing no mortality of a population of earthworms under the conditions of the test), LC₅₀ (the concentration of the test substance that is expected to results in mortality of 50% of a population of earthworms under the conditions of the test) and LC₁₀₀ (the lowest concentration of the test substance causing 100% of mortality of a population of earthworms under the conditions of the test), were determined. It was found that influence of tested plant protection products on earthworms was diversified.