A number of resins have been synthesized by reacting melamine with diamine and formaldehyde in presence of HCl as catalyst, proved to be selective anion-exchange resins for certain metals. The present paper reports the synthesis and ion exchange properties of a resin derived from melamine and phenylenediamine with formaldehyde. The resin MOPDAF, MMPDAF and MPPDAF were synthesized by the condensation of ortho-, meta-, and paraphenylenediamine, respectively with formaldehyde and melamine in the presence of a hydrochloric acid catalyst. These resins were characterized by elemental analysis and antimicrobial activity against several bacterial strains as (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis) and fungal strains as (Aspergillus niger, Neurospora crassa).