The paper presents cutting forces simulation method for valve seats machining. Cutting forces affecting on tool used for valve seats machining and mathematical relations used for simulating forces were described. Tool used for valve seats machining was presented and machining process was described. Analysis of tool setting against machined valve seat impact on area of the chip on tool blades was made by simulation. Simulated cutting forces for different tool settings against machined valve seat were presented. Test stand for verifying simulated cutting forces against measured cutting forces was characterized. General conclusions arising from simulations and further research plans were presente