Amino acid biostimulator based on protein hydrolyzate of keratin from feather waste was used in radish (Raphanus savitus) and wheat (Triticum aestivum L) to study the plants length, mass of germinated plants and the level of chlorophyll. Effect of biostimulator on mortality and body mass of earthworms Eisenia fetida was also tested. Use of the biostimulator in cultivation of plants resulted in an increase in the biomass yield and chlorophyll level. Neither phytotoxicity nor toxicity against earthworms was obsd.