The study presents the original research results of morphological parameters of activated sludge flocs taken from the Wastewater Treatment Plant located in Brzeg Dolny. It has been shown that activated sludge suspension consisted of small flocs below 10 μm in proportion of fibrous and circular shape with low edge roughness. Among the flocs from 10 μm to 100 μm with increasing diameter increased elongation and roughness, and decreased circularity. Flocs of large diameter were very rare. Their size is generally due to a large presence of filamentous bacteria, which were found in abundance in the presented samples of activated sludge. Studies have confirmed that the use of automated image analyzer allows for a detailed analysis of the activated sludge flocs size and shape.