The production of compost from biodegradable municipal waste is not only important for reducing the amount of landfilled waste. Compost produced with the right technology can replenish the missing organic matter in the soil and improve its properties. This paper deals with the evaluation of the phytotoxicity of composts from garden and kitchen biodegradable wastes. Their effect on plant germination and overall plant condition under laboratory conditions was investigated. Samples of compost from the industrial composting plant of the city of Nitra and compost from the electric composter GG02 were used for this test. The tested composts were mixed with the reference substrate in different concentrations and applied to two plant species - Lettuce (Lactuca sativa) and Barley (Hordeum vulgare). After 21 days, the number of germinated plants (i.e. germination rate), the length of the aerial part of the plants, the weight of fresh biomass and also its weight after drying were evaluated. The highest lettuce germination rate was obtained with 25% of the compost from the industrial composting plant. Barley achieved the best germination rate at up to 50% concentration of this compost. However, the highest biomass weight was obtained for barley in the reference sample, i.e. without the addition of compost. On the contrary, the application of compost from the industrial composting plant on lettuce, regardless of its concentration, had a clear stimulating effect, in all the parameters studied. Compost from the electric composter at concentrations of 25% and 50% had an inhibitory effect on all tested parameters of both plants.