Constrained　groove　pressing　(CGP)　has　been　developed　to　refine　grain　sizes,　and　in　most　cases　is　conducted　under　partially　constrained　conditions.　Here　we　report　the　first　investigation　of　the　Von　Mises　equivalent　strain　and　its　distribution　in　samples　subject　to　CGP　under　partially　constrained　conditions.　Using　finite　element　modeling,　we　show　that　the　value　of　the　equivalent　strain　and　its　distribution　depend　strongly　on　the　constraint　condition　of　CGP.　Experiments　using　an　annealed　H62　brass　confirm　the　simulation　and　reveal　that　the　non-uniform　strain　distribution　results　in　the　corresponding　non-uniform　profile　of　the　grain　size　and　hardness.　These　findings　are　of　great　importance　since　many　CGP　are　conducted　under　partially　constrained　conditions　which　generate　lower　equivalent　strains　than　the　counterpart　under　fully　constrained　conditions.　©　2010　Elsevier　B.V.　All　rights　reserved.