Novel flocculants for wastewater and industrial effluents treatment have been developed in authors’ laboratory based on modified polysaccharides. These flocculants have unique characteristics i.e. they are efficient with low dose usage like synthetic flocculants (e.g. polyacrylamide) and controlled biodegradable, shear resistant and inexpensive like polysaccharides. As contaminants have varying ionocity, various kinds of nonionic, anionic and cationic flocculants have been developed in authors’ laboratory. The recent approaches on the removal of toxic materials, removal of colour and reduction of total pollutant content from various wastewaters using modified polysaccharides is becoming more important in the present frontier research, because of their worst impact towards environment as well as human health. The present article deals with the recent developments which took place in authors’ laboratory on the synthesis of novel cationic flocculants based on modified polysaccharides derived from starch, amylose, amylopectin, chitosan, guar gum, glycogen, and tamarind kernel. The applications of these modified polysaccharides as flocculants for the treatment of various wastewaters including municipal sewage wastewater and as adsorbent for removal of reactive black dye from its aqueous solution have been discussed. The main objective of this article is to provide recent information about the most important features of these polymeric materials developed in authors’ laboratory and to show the advantages gained from the use of flocculants based on cationic polysaccharides in wastewater treatment.