The copper based alloy containing lead, iron and arsenic is the intermediate product in the recovery of copper from the slag of flash smelting process. The arsenic removal from this alloy may be executed by means of the reaction with titanium or zirconium. In order to analyze this possibility the basic knowledge on As-Cu-Ti and As-Cu-Zr equilibrium diagrams is necessary. However, the data on high temperature regions of these systems are lacking. The aim of the present work is to estimate these phase diagrams based on own experiments, in which the compositions of phases in equilibrium under applied arsenic pressures in closed systems were determined. Arsenic pressure in the system was controlled either through the temperature of pure arsenic in nonisothermal experiment, or through its activity in As-Cu matrix alloy in isothermal experiment. The phases' compositions were then obtained from X-ray microanalysis of quenched samples. As a result, the points of liquidus lines for binary As-Ti and As-Zr alloys were determined and from these the arsenic activities calculated in the liquid phase. The provisional versions of binary As-Ti and As-Zr phase diagrams is suggested. The experiment for As-Ti-Cu system revealed, that AsTi compound is in equilibrium with copper rich liquid.