The addition of different concentrations of industrial wastewater of the gelatin and colloids factory to batch cultures of some algal populations of Ismailia Canal water, grown under optimum laboratory conditions, resulted generally in remarkable alterations in the species composition, total algal counts and percentage composition of the main algal taxa of these populations. Such effects were reflected in the disappearance of some species and the decease or increase in cell counts of other species. The total algal count was increased at low and moderate concentrations (10%, 20% and 40%) but was decreased at high concentrations (60% and 80%). Species number was decreased in all treated cultures relevant to that of the control. Such drop was progressively increased with further rise in the concentration of the industrial waste.  Within all concentrations of the industrial waste of Gelatin and colloids factory the recorded species exhibited variable degrees of tolerance. Generally, out of all species, 34 species were tolerant whereas 12 species were moderately sensitive, on the other hand, 26 species were highly sensitive.