diff --git a/lib/core/common.py b/lib/core/common.py
index aba01041a..b78f45a20 100644
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -33,6 +33,7 @@ import time
 import urlparse
 
 
+from lib.core.convert import urldecode
 from lib.core.data import conf
 from lib.core.data import kb
 from lib.core.data import logger
@@ -497,7 +498,7 @@ def parseTargetUrl():
         conf.port = 80
 
     if __urlSplit[3]:
-        conf.parameters["GET"] = __urlSplit[3].replace("%", "%%")
+        conf.parameters["GET"] = urldecode(__urlSplit[3]).replace("%", "%%")
 
     conf.url = "%s://%s:%d%s" % (conf.scheme, conf.hostname, conf.port, conf.path)
 
diff --git a/lib/core/convert.py b/lib/core/convert.py
index 258237aa0..449fc73f1 100644
--- a/lib/core/convert.py
+++ b/lib/core/convert.py
@@ -72,7 +72,11 @@ def urldecode(string):
     if not string:
         return
 
-    return urllib.unquote_plus(string)
+    doublePercFreeString = string.replace("%%", "__DPERC__")
+    unquotedString = urllib.unquote_plus(doublePercFreeString)
+    unquotedString = unquotedString.replace("__DPERC__", "%%")
+
+    return unquotedString
 
 
 def urlencode(string, safe=":/?%&="):
diff --git a/lib/core/target.py b/lib/core/target.py
index c94773ff6..36364d7e2 100644
--- a/lib/core/target.py
+++ b/lib/core/target.py
@@ -32,6 +32,7 @@ from lib.core.common import dataToSessionFile
 from lib.core.common import paramToDict
 from lib.core.common import parseTargetUrl
 from lib.core.common import readInput
+from lib.core.convert import urldecode
 from lib.core.data import conf
 from lib.core.data import kb
 from lib.core.data import logger
@@ -66,8 +67,9 @@ def __setRequestParams():
         raise sqlmapSyntaxException, errMsg
 
     if conf.data:
-        conf.parameters["POST"] = conf.data.replace("%", "%%")
-        __paramDict = paramToDict("POST", conf.data)
+        urlDecodedData = urldecode(conf.data).replace("%", "%%")
+        conf.parameters["POST"] = urlDecodedData
+        __paramDict = paramToDict("POST", urlDecodedData)
 
         if __paramDict:
             conf.paramDict["POST"] = __paramDict
@@ -75,8 +77,9 @@ def __setRequestParams():
 
     # Perform checks on Cookie parameters
     if conf.cookie:
-        conf.parameters["Cookie"] = conf.cookie.replace("%", "%%")
-        __paramDict = paramToDict("Cookie", conf.cookie)
+        urlDecodedCookie = urldecode(conf.cookie).replace("%", "%%")
+        conf.parameters["Cookie"] = urlDecodedCookie
+        __paramDict = paramToDict("Cookie", urlDecodedCookie)
 
         if __paramDict:
             conf.paramDict["Cookie"] = __paramDict
@@ -86,7 +89,7 @@ def __setRequestParams():
     if conf.httpHeaders:
         for httpHeader, headerValue in conf.httpHeaders:
             if httpHeader == "User-Agent":
-                conf.parameters["User-Agent"] = headerValue.replace("%", "%%")
+                conf.parameters["User-Agent"] = urldecode(headerValue).replace("%", "%%")
 
                 condition  = not conf.testParameter
                 condition |= "User-Agent" in conf.testParameter