A copolymer was synthesized from o-cresol and adipamide using formaldehyde as a cross linking agent at 130 ± 2 0C in 2M HCl medium. The resin was characterized by elemental analysis, FTIR and NMR spectra. The morphology of the synthesized resin was studied by optical photograph and scanning electron microscopy (SEM). The o-CAF resin was tested for its inhibitory action against pathogenic bacteria and fungi. The resin show potent inhibitory action against bacteria such as Escherichia coli, Klebseilla, Staphylococcus aureus and Pseudomonas aeruginosa and fungi viz. Aspergillus flavus, Aspergillus niger, Pencillium species, Candida albicans, Cryptococcus neoformans and Mucor species. The total cation exchange capacity was measured and effect of pH and metal ion concentration on ion-exchange capacity were studied. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer resin is soluble in DMF, DMSO, THF, conc. H2SO4.