The sinter hardening response of PM steels is affected by alloying system, cooling rate, density and mass of the component. In this paper the sinter hardening response of two chromium alloyed PM steels has been investigated when the mass and density are varied. Components of different size and green densities have been sinter hardened under production conditions for comparison. Macro hardness and micro structural transformations for each of the parts were evaluated to characterize the response. The objective of this work is to provide an aid for selecting correct sinter hardening material and processing conditions for a given application.