diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index 481ceb9f..bfb696da 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -254,6 +254,8 @@ static const CRPCCommand vRPCCommands[] =
     { "sendrawtransaction",     &sendrawtransaction,     false,  false },
     { "gettxoutsetinfo",        &gettxoutsetinfo,        true,   false },
     { "gettxout",               &gettxout,               true,   false },
+    { "lockunspent",            &lockunspent,            false,  false },
+    { "listlockunspent",        &listlockunspent,        false,  false },
 };
 
 CRPCTable::CRPCTable()
@@ -1215,6 +1217,8 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
     if (strMethod == "signrawtransaction"     && n > 2) ConvertTo<Array>(params[2], true);
     if (strMethod == "gettxout"               && n > 1) ConvertTo<boost::int64_t>(params[1]);
     if (strMethod == "gettxout"               && n > 2) ConvertTo<bool>(params[2]);
+    if (strMethod == "lockunspent"            && n > 0) ConvertTo<bool>(params[0]);
+    if (strMethod == "lockunspent"            && n > 1) ConvertTo<Array>(params[1]);
 
     return params;
 }
diff --git a/src/bitcoinrpc.h b/src/bitcoinrpc.h
index dc4dc303..44050ae1 100644
--- a/src/bitcoinrpc.h
+++ b/src/bitcoinrpc.h
@@ -177,6 +177,8 @@ extern json_spirit::Value getinfo(const json_spirit::Array& params, bool fHelp);
 
 extern json_spirit::Value getrawtransaction(const json_spirit::Array& params, bool fHelp); // in rcprawtransaction.cpp
 extern json_spirit::Value listunspent(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value lockunspent(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value listlockunspent(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value createrawtransaction(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value decoderawtransaction(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value signrawtransaction(const json_spirit::Array& params, bool fHelp);
diff --git a/src/rpcwallet.cpp b/src/rpcwallet.cpp
index d597e5e3..90a68f56 100644
--- a/src/rpcwallet.cpp
+++ b/src/rpcwallet.cpp
@@ -3,14 +3,18 @@
 // Distributed under the MIT/X11 software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <boost/assign/list_of.hpp>
+
 #include "wallet.h"
 #include "walletdb.h"
 #include "bitcoinrpc.h"
 #include "init.h"
 #include "base58.h"
 
-using namespace json_spirit;
 using namespace std;
+using namespace boost;
+using namespace boost::assign;
+using namespace json_spirit;
 
 int64 nWalletUnlockTime;
 static CCriticalSection cs_nWalletUnlockTime;
@@ -1497,3 +1501,74 @@ Value validateaddress(const Array& params, bool fHelp)
     return ret;
 }
 
+Value lockunspent(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() < 1 || params.size() > 2)
+        throw runtime_error(
+            "lockunspent unlock? [array-of-Objects]\n"
+            "Updates list of temporarily unspendable outputs.");
+
+    if (params.size() == 1)
+        RPCTypeCheck(params, list_of(bool_type));
+    else
+        RPCTypeCheck(params, list_of(bool_type)(array_type));
+
+    bool fUnlock = params[0].get_bool();
+
+    if (params.size() == 1) {
+        if (fUnlock)
+            pwalletMain->UnlockAllCoins();
+        return true;
+    }
+
+    Array outputs = params[1].get_array();
+    BOOST_FOREACH(Value& output, outputs)
+    {
+        if (output.type() != obj_type)
+            throw JSONRPCError(-8, "Invalid parameter, expected object");
+        const Object& o = output.get_obj();
+
+        RPCTypeCheck(o, map_list_of("txid", str_type)("vout", int_type));
+
+        string txid = find_value(o, "txid").get_str();
+        if (!IsHex(txid))
+            throw JSONRPCError(-8, "Invalid parameter, expected hex txid");
+
+        int nOutput = find_value(o, "vout").get_int();
+        if (nOutput < 0)
+            throw JSONRPCError(-8, "Invalid parameter, vout must be positive");
+
+        COutPoint outpt(uint256(txid), nOutput);
+
+        if (fUnlock)
+            pwalletMain->UnlockCoin(outpt);
+        else
+            pwalletMain->LockCoin(outpt);
+    }
+
+    return true;
+}
+
+Value listlockunspent(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() > 0)
+        throw runtime_error(
+            "listlockunspent\n"
+            "Returns list of temporarily unspendable outputs.");
+
+    vector<COutPoint> vOutpts;
+    pwalletMain->ListLockedCoins(vOutpts);
+
+    Array ret;
+
+    BOOST_FOREACH(COutPoint &outpt, vOutpts) {
+        Object o;
+
+        o.push_back(Pair("txid", outpt.hash.GetHex()));
+        o.push_back(Pair("vout", (int)outpt.n));
+        ret.push_back(o);
+    }
+
+    return ret;
+}
+
diff --git a/src/wallet.cpp b/src/wallet.cpp
index cedda9e9..c07adff6 100644
--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -957,9 +957,11 @@ void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed) const
             if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                 continue;
 
-            for (unsigned int i = 0; i < pcoin->vout.size(); i++)
-                if (!(pcoin->IsSpent(i)) && IsMine(pcoin->vout[i]) && pcoin->vout[i].nValue > 0)
+            for (unsigned int i = 0; i < pcoin->vout.size(); i++) {
+                if (!(pcoin->IsSpent(i)) && IsMine(pcoin->vout[i]) &&
+                    !IsLockedCoin((*it).first, i) && pcoin->vout[i].nValue > 0)
                     vCoins.push_back(COutput(pcoin, i, pcoin->GetDepthInMainChain()));
+            }
         }
     }
 }
@@ -1770,3 +1772,35 @@ void CWallet::UpdatedTransaction(const uint256 &hashTx)
             NotifyTransactionChanged(this, hashTx, CT_UPDATED);
     }
 }
+
+void CWallet::LockCoin(COutPoint& output)
+{
+    setLockedCoins.insert(output);
+}
+
+void CWallet::UnlockCoin(COutPoint& output)
+{
+    setLockedCoins.erase(output);
+}
+
+void CWallet::UnlockAllCoins()
+{
+    setLockedCoins.clear();
+}
+
+bool CWallet::IsLockedCoin(uint256 hash, unsigned int n) const
+{
+    COutPoint outpt(hash, n);
+
+    return (setLockedCoins.count(outpt) > 0);
+}
+
+void CWallet::ListLockedCoins(std::vector<COutPoint>& vOutpts)
+{
+    for (std::set<COutPoint>::iterator it = setLockedCoins.begin();
+         it != setLockedCoins.end(); it++) {
+        COutPoint outpt = (*it);
+        vOutpts.push_back(outpt);
+    }
+}
+
diff --git a/src/wallet.h b/src/wallet.h
index 05d60056..ecfdafe2 100644
--- a/src/wallet.h
+++ b/src/wallet.h
@@ -119,11 +119,18 @@ public:
 
     CPubKey vchDefaultKey;
 
+    std::set<COutPoint> setLockedCoins;
+
     // check whether we are allowed to upgrade (or already support) to the named feature
     bool CanSupportFeature(enum WalletFeature wf) { return nWalletMaxVersion >= wf; }
 
     void AvailableCoins(std::vector<COutput>& vCoins, bool fOnlyConfirmed=true) const;
     bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, std::vector<COutput> vCoins, std::set<std::pair<const CWalletTx*,unsigned int> >& setCoinsRet, int64& nValueRet) const;
+    bool IsLockedCoin(uint256 hash, unsigned int n) const;
+    void LockCoin(COutPoint& output);
+    void UnlockCoin(COutPoint& output);
+    void UnlockAllCoins();
+    void ListLockedCoins(std::vector<COutPoint>& vOutpts);
 
     // keystore implementation
     // Generate a new key