In the modern society of technological progress, anthropogenic activities are leading to increasing water pollution. Leachates originating from the organic fraction of mixed municipal waste are highly contaminated and require physical, chemical or biological treatment before being discharged into the environment. Bioremediation technology is becoming increasingly important in overcoming these challenges as it offers a sustainable and highly effective solution for the remediation of various types of pollution. Pollutants, through processes of biodegradation or biotransformation, are converted into non-toxic products and byproducts through the enzymatic catabolic potential of microorganisms. To enhance the speed and effectiveness of bioremediation technology, additional tools are introduced, such as the optimisation of process factors through biostimulation and the use of indigenous or exogenous cultures as inoculants in bioaugmentation. In this work, the bioremediation of leachate from the organic fraction of mixed municipal waste was investigated. The effectiveness of the removal of organic pollution removal with bioaugmentation with exogenous microbial cultures Pseudomonas putida and activated sludge was compared. The experiments were carried out in a batch reactor under submerged conditions for 10 days. The average overall efficiency of the organic matter removal in the investigated systems was 89 %. The conducted research provides insights into the practical application of bioremediation and contributes to the further development of wastewater treatment strategies.