Determination of ferrous iron in sillcates containing S and Cu was studied.A two step procedure was given .The sample (S<5%) was first treated with HAc-HF-HGI-NH4F;if the sample containing S more khan X% was treated with H2SO4-CnSO4-HF;and acid solubie ferrous iron was titrated"with standard potassium dichiomiate solution; then the residue was fitteed out and igaited,which turns sulfide into oxide, then the iron oxide was dissolved in acid and detertizined by potassiura dichromate titration. Tie ferrous. iron content was calcuited as the total of both results.