Abstract: This invention relates to a convenient and improved process for preparation of glatiramer acetate (copolymer-1) of pharmaceutical grade. The process involves polymerizing N-carboxyanhydrides of tyrosine, alanine, y-benzyl glutamate and &egr;-N-trifluoroacetyllysine in dioxane with diethylamine as initiator to afford protected copolymer-1. Treatment with hydrogen bromide in acetic acid at 35° C. for 3-5 h cleaves benzyl group to produce trifluoroacetyl copolymer-1. The trifluoroacetyl copolymer-1 is washed with an organic solvent to remove reactive benzyl bromide generated during debenzylation. Deprotection with aqueous piperidine, followed by dialysis offers glatiramer acetate (copolymer-1) of Molecular weight 5000-9000 daltons.