diff --git a/lib/web3/errors.js b/lib/web3/errors.js
index 72a63a5..09bd899 100644
--- a/lib/web3/errors.js
+++ b/lib/web3/errors.js
@@ -21,8 +21,11 @@
  */
 
 module.exports = {
-    InvalidNumberOfParams: function () {
-        return new Error('Invalid number of input parameters');
+    InvalidNumberOfSolidityArgs: function () {
+        return new Error('Invalid number of arguments to Solidity function');
+    },
+    InvalidNumberOfRPCParams: function () {
+        return new Error('Invalid number of input parameters to RPC method');
     },
     InvalidConnection: function (host){
         return new Error('CONNECTION ERROR: Couldn\'t connect to node '+ host +'.');
diff --git a/lib/web3/function.js b/lib/web3/function.js
index 6069886..a480c86 100644
--- a/lib/web3/function.js
+++ b/lib/web3/function.js
@@ -22,6 +22,7 @@
 
 var coder = require('../solidity/coder');
 var utils = require('../utils/utils');
+var errors = require('./errors');
 var formatters = require('./formatters');
 var sha3 = require('../utils/sha3');
 
@@ -54,6 +55,23 @@ SolidityFunction.prototype.extractDefaultBlock = function (args) {
     }
 };
 
+/**
+ * Should be called to check if the number of arguments is correct
+ *
+ * @method validateArgs
+ * @param {Array} arguments
+ * @throws {Error} if it is not
+ */
+SolidityFunction.prototype.validateArgs = function (args) {
+    var inputArgs = args.filter(function (a) {
+      // filter the options object but not arguments that are arrays
+      return !(utils.isObject(a) === true && utils.isArray(a) === false);
+    });
+    if (inputArgs.length !== this._inputTypes.length) {
+        throw errors.InvalidNumberOfSolidityArgs();
+    }
+};
+
 /**
  * Should be used to create payload from arguments
  *
@@ -66,6 +84,7 @@ SolidityFunction.prototype.toPayload = function (args) {
     if (args.length > this._inputTypes.length && utils.isObject(args[args.length -1])) {
         options = args[args.length - 1];
     }
+    this.validateArgs(args);
     options.to = this._address;
     options.data = '0x' + this.signature() + coder.encodeParams(this._inputTypes, args);
     return options;
@@ -259,4 +278,3 @@ SolidityFunction.prototype.attachToContract = function (contract) {
 };
 
 module.exports = SolidityFunction;
-
diff --git a/lib/web3/method.js b/lib/web3/method.js
index ebedd02..2e3c796 100644
--- a/lib/web3/method.js
+++ b/lib/web3/method.js
@@ -69,7 +69,7 @@ Method.prototype.extractCallback = function (args) {
  */
 Method.prototype.validateArgs = function (args) {
     if (args.length !== this.params) {
-        throw errors.InvalidNumberOfParams();
+        throw errors.InvalidNumberOfRPCParams();
     }
 };
 
@@ -162,4 +162,3 @@ Method.prototype.request = function () {
 };
 
 module.exports = Method;
-
diff --git a/test/contract.js b/test/contract.js
index f392dc2..a7e7247 100644
--- a/test/contract.js
+++ b/test/contract.js
@@ -4,6 +4,7 @@ var Web3 = require('../index');
 var FakeHttpProvider = require('./helpers/FakeHttpProvider');
 var FakeHttpProvider2 = require('./helpers/FakeHttpProvider2');
 var utils = require('../lib/utils/utils');
+var errors = require('../lib/web3/errors');
 var BigNumber = require('bignumber.js');
 var sha3 = require('../lib/utils/sha3');
 
@@ -353,6 +354,31 @@ describe('contract', function () {
 
         });
 
+        it('should throw if called with optional params without all args', function () {
+            var provider = new FakeHttpProvider();
+            var web3 = new Web3(provider); 
+            provider.injectResult('0x0000000000000000000000000000000000000000000000000000000000000032');
+            var signature = 'balance(address)';
+            var address = '0x1234567890123456789012345678901234567891';
+            provider.injectValidation(function (payload) {
+                assert.equal(payload.method, 'eth_call');
+                assert.deepEqual(payload.params, [{
+                    data: '0x' + sha3(signature).slice(0, 8) + '0000000000000000000000001234567890123456789012345678901234567891',
+                    to: address,
+                    from: address,
+                    gas: '0xc350'
+                }, 'latest']);
+            });
+
+            var contract = web3.eth.contract(desc).at(address);
+            
+            var test = function() {
+              var r = contract.balance({from: address, gas: 50000});
+            }
+            assert.throws(test, errors.InvalidNumberOfSolidityArgs().message);
+
+        });
+
         it('should explicitly make a call with optional params', function () {
             var provider = new FakeHttpProvider();
             var web3 = new Web3(provider); 
@@ -399,6 +425,35 @@ describe('contract', function () {
 
         });
 
+        it('it should throw if sendTransaction with optional params without all args', function () {
+            var provider = new FakeHttpProvider();
+            var web3 = new Web3(provider);
+            var signature = 'send(address,uint256)';
+            var address = '0x1234567890123456789012345678901234567891';
+            provider.injectValidation(function (payload) {
+                assert.equal(payload.method, 'eth_sendTransaction');
+                assert.deepEqual(payload.params, [{
+                    data: '0x' + sha3(signature).slice(0, 8) +
+                        '0000000000000000000000001234567890123456789012345678901234567891' +
+                        '0000000000000000000000000000000000000000000000000000000000000011' ,
+                    to: address,
+                    from: address,
+                    gas: '0xc350',
+                    gasPrice: '0xbb8',
+                    value: '0x2710'
+                }]);
+            });
+
+            var contract = web3.eth.contract(desc).at(address);
+
+            var test = function() {
+              contract.send(address, {from: address, gas: 50000, gasPrice: 3000, value: 10000});
+            }
+
+            assert.throws(test, errors.InvalidNumberOfSolidityArgs().message);
+
+        });
+
         it('should sendTransaction with optional params', function () {
             var provider = new FakeHttpProvider();
             var web3 = new Web3(provider); 
@@ -557,4 +612,3 @@ describe('contract', function () {
         });
     });
 });
-
diff --git a/test/method.validateArgs.js b/test/method.validateArgs.js
index cd4882c..d3d72a0 100644
--- a/test/method.validateArgs.js
+++ b/test/method.validateArgs.js
@@ -39,9 +39,8 @@ describe('lib/web3/method', function () {
             var test2 = function () { method.validateArgs(args2); };
             
             // then
-            assert.throws(test, errors.InvalidNumberOfParams().message);
-            assert.throws(test2, errors.InvalidNumberOfParams().message);
+            assert.throws(test, errors.InvalidNumberOfRPCParams().message);
+            assert.throws(test2, errors.InvalidNumberOfRPCParams().message);
         });
     });
 });
-