A　sensitive　and　selective　method　for　the　determination　of　procaine　hydrochloride　with　a　Nafion-modified　glassy　carbon　electrode　has　been　developed.　The　voltammetric　behavior　of　procaine　hydrochloride　on　the　Nafion-modified　electrode　indicated　that　the　modified　electrode　not　only　increased　the　sensitivity　of　the　determination　of　procaine　hydrochloride,　but　also　catalyzed　the　electrode　process.　Procaine　hydrochloride　was　accumulated　in　Britton-Robinson　buffer　(pH　2.09)　at　a　potential　of　-0.2　V　(vs.　SCE)　for　180　s,　and　was　then　determined　by　differential　pulse　adsorptive　stripping　voltammetry.　The　effect　of　various　parameters,　such　as　the　pH　of　the　medium,　the　mass　of　drop-coated　Nafion,　the　accumulation　potential,　the　accumulation　time　and　the　scan　rate,　were　investigated.　Under　the　optimum　conditions,　a　linear　calibration　graph　was　obtained　in　the　concentration　range　of　6.0　×　10　-8　to　6.0　×　10　-6　mol　1　-1　with　a　correlation　coefficient　of　0.9987.　The　relative　standard　deviation　was　4.18%　for　eight　successive　determinations　of　1.0　×　10　-7　mol　1　-1　procaine　hydrochloride,　and　the　detection　limit　(three　times　signal　to　noise)　was　7.0　×　10　-9　mol　1　-1　.　A　study　of　interfering　substances　was　also　performed,　and　the　method　was　applied　to　the　direct　determinations　of　procaine　hydrochloride　in　the　injection　solution　of　procaine　hydrochloride　and　in　rabbit　serum.