This study aims to estimate the degradation process of polylactide (PLA) in natural aqueous environments. The biological degradation of PLA took place in the Baltic Sea and in the natural pond over a period of 1 to 16 months. The characteristic abiotic parameters of both environments were monitored during incubation time, and their influence on the PLA degradation was discussed. The changes in weight, chemical structure, mechanical properties and surface morphology of investigated samples were also tested during incubation. The obtained results indicate that polylactide is not very susceptible to an enzymatic attack of microorganisms present in natural aqueous environments.