Studies were conducted on the occurrence, secondary production and utilisation of different groups of dissolved free amino acids (DFAA) and carbohydrates (DFCHO) by epi-phytic bacteria inhabiting three different freshwater plants. The maximum total number of epi-phytic bacteria was found in summer on the abaxial surfaces of Nuphar luteum leaves. The minimum density of bacteria was found on mature shoots of Potamogeton lucens in summer and autumn. The highest bacterial production was achieved in autumn on the lower sections of Phragmites australis. DFAA utilisation was more intensive in spring. In general, DFCHO were poorly utilised in all seasons.