A　cyanide-free　silver　plating　bath　containing　uracil　as　a　complexing　agent　was　investigated.　The　electrochemical　properties　of　a　silver　complex　were　studied　on　a　disk　glassy　carbon　electrode　by　means　of　cyclic　voltammetry　and　a　rotating　disk　electrode.　The　brightness　and　adhesion　of　silver　deposits　obtained　from　this　silver　plating　bath　onto　copper　substrates　in　the　absence　and　presence　of　polyethyleneimine　(PEI)　were　evaluated.　Mirror-bright　and　good　adherent　silver　deposits　could　be　obtained　without　a　separate　strike　plating　process　when　PEI　as　an　additive　was　added.　Differential　capacitance　studies　indicated　that　competition　adsorption　between　PEI　and　uracil　molecules　occurred　on　the　silver　surface.　The　electrochemical　displacement　rate　of　silver　by　base　metal　(e.g.,　copper)　was　very　slow　compared　with　that　in　a　typical　cyanide　strike　bath　from　the　results　of　electrochemical　quartz　crystal　microbalance　studies.　The　surface　morphology　of　silver　deposits　characterized　by　scanning　electron　microscopy　illustrated　that,　with　the　addition　of　PEI,　the　grain　size　of　the　deposits　decreased　from　hundreds　to　tens　of　nanometers.　©　2008　The　Electrochemical　Society.