In this study, proteolytic activity of Trichomonas tenax collected directly from patient's dentobacterial plaque was examined. Electrophoretic method involving polyacrylamide gels (Commassie Brilliant Blue R-250) and electrophoretic method involving gelatin-containing polyacrylamide gels, have been used to analyse Trichomonas tenax proteolytic activity. The most obvious and the fastest activities were obtained when gels were incubated in pH 4.6; followed by results of incubating in pH 5.6; while in pH 2.8 activity was less effective but still obvious. Proteolytic activities were the most effective in area of protein MW 36 kDa. Different activities of enzymes depending on pH of incubated media indicate the presence of different endopeptidases in cell lysates of protozoon Trichomonas tenax from dentobacterial plaque.