Cationic microgels of p(3-Acrylamidopropy1)-trimethylammonium chloride (p(APTMACI)) were synthesized using the inverse suspension polymerization technique, and the obtained microgels were used as microreactor for in situ synthesis of Co, Ni, and Cu nanoparticles. The p(APTMAC1) microgels were loaded with Co,.Ni, and Cu after contact with chloride salts of the metals, CoCl2, NiCl2, and CuCl2, in ethanol and reduced to their respective metal nanoparticles by treating them with sodium borohydride (NaBH4) as reducing agent. The metal nanoparticle content of p(APTMAC1) microparticles were quantified for each composites by atomic absorption spectroscopy (AAS) after dissolution of the metal nanoparticles within microgel composites by concentrated hydrochloric acid (HCI). Dynamic light scattering (DIS) was used to monitor zeta potential of the microgel composites. Thermal properties of both cationic p(APTMAC1) microgel and its composites were investigated with a thermal gravimetric analyzer (TGA). It was also found that the p(APTMAC1) composites performed as excellent catalyst systems in the reduction of different aromatic pollutants like 2-nitrophenol, 4-nitrophenol and fluorescent dyes like eosin Y(EY), and methyl orange (MO). Various parameters such as metal types, and their respective amount, and temperature were investigated to determine the catalytic performances of the microgel-metal nanoparticle composites. (C) 2014 Elsevier B.V. All rights reserved.