diff --git a/lib/server.js b/lib/server.js
index d0529c3..4874759 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -1444,33 +1444,44 @@ WalletService.prototype.sendTx = function(opts, cb) {
     return cb(new ClientError('Required argument missing'));
 
   self._runLocked(cb, function(cb) {
-    self.storage.fetchTx(self.walletId, opts.txProposalId, function(err, txp) {
+    self.getWallet({}, function(err, wallet) {
       if (err) return cb(err);
-      if (!txp) return cb(Errors.TX_NOT_FOUND);
-      if (!txp.isTemporary()) return cb();
-
-      var raw = txp.getRawTx();
-      var validSignature = self._verifySignature(raw, opts.proposalSignature, opts.proposalSignaturePubKey);
-      if (!validSignature) {
-        return cb(new ClientError('Invalid proposal signature'));
-      }
 
-      // Verify UTXOs are still available
-      self.getUtxos({}, function(err, utxos) {
+      self.storage.fetchTx(self.walletId, opts.txProposalId, function(err, txp) {
         if (err) return cb(err);
+        if (!txp) return cb(Errors.TX_NOT_FOUND);
+        if (!txp.isTemporary()) return cb();
+
+        // Validate that the pubkey used to sign the proposal actually belongs to the copayer
+        var copayer = wallet.getCopayer(self.copayerId);
+        var validPubKey = !!self._getSigningKey(opts.proposalSignaturePubKey, opts.proposalSignaturePubKeySig, copayer.requestPubKeys);
+        if (!validPubKey) {
+          return cb(new ClientError('Invalid proposal signing key'));
+        }
 
-        var txpInputs = _.map(txp.inputs, utxoKey);
-        var lockedUtxoIndex = _.indexBy(_.filter(utxos, 'locked'), utxoKey);
-        var unavailable = _.any(txpInputs, function(i) {
-          return lockedUtxoIndex[i];
-        });
-
-        if (unavailable) return cb(Errors.UNAVAILABLE_UTXOS);
+        var raw = txp.getRawTx();
+        var validSignature = self._verifySignature(raw, opts.proposalSignature, opts.proposalSignaturePubKey);
+        if (!validSignature) {
+          return cb(new ClientError('Invalid proposal signature'));
+        }
 
-        txp.status = 'pending';
-        self.storage.storeTx(self.walletId, txp, function(err) {
+        // Verify UTXOs are still available
+        self.getUtxos({}, function(err, utxos) {
           if (err) return cb(err);
-          return cb();
+
+          var txpInputs = _.map(txp.inputs, utxoKey);
+          var lockedUtxoIndex = _.indexBy(_.filter(utxos, 'locked'), utxoKey);
+          var unavailable = _.any(txpInputs, function(i) {
+            return lockedUtxoIndex[i];
+          });
+
+          if (unavailable) return cb(Errors.UNAVAILABLE_UTXOS);
+
+          txp.status = 'pending';
+          self.storage.storeTx(self.walletId, txp, function(err) {
+            if (err) return cb(err);
+            return cb();
+          });
         });
       });
     });
diff --git a/test/integration/helpers.js b/test/integration/helpers.js
index 882a94f..508c579 100644
--- a/test/integration/helpers.js
+++ b/test/integration/helpers.js
@@ -397,13 +397,14 @@ helpers.createProposalOpts2 = function(outputs, moreOpts, inputs) {
 helpers.getProposalSignatureOpts = function(txp, signingKey) {
   var raw = txp.getRawTx();
   var proposalSignature = helpers.signMessage(raw, signingKey);
-  var x = new Bitcore.PrivateKey(signingKey).toPublicKey().toString();
+  var pubKey = new Bitcore.PrivateKey(signingKey).toPublicKey().toString();
+  var pubKeySig = helpers.signMessage(pubKey, signingKey);
 
   return {
     txProposalId: txp.id,
     proposalSignature: proposalSignature,
-    proposalSignaturePubKey: new Bitcore.PrivateKey(signingKey).toPublicKey().toString(),
-    proposalSignaturePubKeySig: 'dummy',
+    proposalSignaturePubKey: pubKey,
+    proposalSignaturePubKeySig: pubKeySig,
   }
 };
 
diff --git a/test/integration/server.js b/test/integration/server.js
index 9d8feb4..888580c 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -2366,7 +2366,7 @@ describe('Wallet service', function() {
       });
     });
 
-    it.only('should be able to send a temporary tx proposal', function(done) {
+    it('should be able to send a temporary tx proposal', function(done) {
       helpers.stubUtxos(server, wallet, [1, 2], function() {
         var txOpts = helpers.createProposalOpts2([{
           toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
@@ -2405,6 +2405,49 @@ describe('Wallet service', function() {
         });
       });
     });
+    it('should fail to send tx proposal with wrong signature', function(done) {
+      helpers.stubUtxos(server, wallet, [1, 2], function() {
+        var txOpts = helpers.createProposalOpts2([{
+          toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
+          amount: 0.8
+        }], {
+          message: 'some message',
+          customData: 'some custom data',
+        });
+        server.createTx(txOpts, function(err, txp) {
+          should.not.exist(err);
+          should.exist(txp);
+          var sendOpts = helpers.getProposalSignatureOpts(txp, TestData.copayers[0].privKey_1H_0);
+          sendOpts.proposalSignature = 'dummy';
+          server.sendTx(sendOpts, function(err) {
+            should.exist(err);
+            err.message.should.contain('Invalid proposal signature');
+            done();
+          });
+        });
+      });
+    });
+    it('should fail to send tx proposal not signed by the creator', function(done) {
+      helpers.stubUtxos(server, wallet, [1, 2], function() {
+        var txOpts = helpers.createProposalOpts2([{
+          toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
+          amount: 0.8
+        }], {
+          message: 'some message',
+          customData: 'some custom data',
+        });
+        server.createTx(txOpts, function(err, txp) {
+          should.not.exist(err);
+          should.exist(txp);
+          var sendOpts = helpers.getProposalSignatureOpts(txp, TestData.copayers[1].privKey_1H_0);
+          server.sendTx(sendOpts, function(err) {
+            should.exist(err);
+            err.message.should.contain('Invalid proposal signing key');
+            done();
+          });
+        });
+      });
+    });
     it('should fail to send a temporary tx proposal if utxos are unavailable', function(done) {
       var txp1, txp2;
       var txOpts = helpers.createProposalOpts2([{
@@ -2432,20 +2475,12 @@ describe('Wallet service', function() {
           txp2 = txp;
           should.exist(txp1);
           should.exist(txp2);
-          server.sendTx({
-            txProposalId: txp1.id,
-            proposalSignature: 'dummy',
-            proposalSignaturePubKey: 'dummy',
-            proposalSignaturePubKeySig: 'dummy',
-          }, next);
+          var sendOpts = helpers.getProposalSignatureOpts(txp1, TestData.copayers[0].privKey_1H_0);
+          server.sendTx(sendOpts, next);
         },
         function(next) {
-          server.sendTx({
-            txProposalId: txp2.id,
-            proposalSignature: 'dummy',
-            proposalSignaturePubKey: 'dummy',
-            proposalSignaturePubKeySig: 'dummy',
-          }, function(err) {
+          var sendOpts = helpers.getProposalSignatureOpts(txp2, TestData.copayers[0].privKey_1H_0);
+          server.sendTx(sendOpts, function(err) {
             should.exist(err);
             err.code.should.equal('UNAVAILABLE_UTXOS');
             next();
@@ -2464,12 +2499,8 @@ describe('Wallet service', function() {
         },
         function(txp3, next) {
           should.exist(txp3);
-          server.sendTx({
-            txProposalId: txp3.id,
-            proposalSignature: 'dummy',
-            proposalSignaturePubKey: 'dummy',
-            proposalSignaturePubKeySig: 'dummy',
-          }, next);
+          var sendOpts = helpers.getProposalSignatureOpts(txp3, TestData.copayers[0].privKey_1H_0);
+          server.sendTx(sendOpts, next);
         },
         function(next) {
           server.getPendingTxs({}, function(err, txs) {
@@ -2484,6 +2515,7 @@ describe('Wallet service', function() {
       });
     });
   });
+
   describe('#createTx backoff time', function(done) {
     var server, wallet, txid;