diff --git a/Docs/src/defines.but b/Docs/src/defines.but
index dbc5b06e..b2ed8f50 100644
--- a/Docs/src/defines.but
+++ b/Docs/src/defines.but
@@ -141,6 +141,12 @@ Creates a macro named 'macro_name'. All lines between the !macro and the !macroe
 
 Ends a macro that was started with !macro.
 
+\S1{macroundef} !macroundef
+
+\c macro_name
+
+Deletes a macro. 
+
 \S1{searchparse} !searchparse
 
 \c [/ignorecase] [/noerrors] [/file] source_string_or_file substring_start OUTPUTSYMBOL1 [substring [OUTPUTSYMBOL2 [substring ...]]]
diff --git a/Source/script.cpp b/Source/script.cpp
index 87320a53..255cf35e 100644
--- a/Source/script.cpp
+++ b/Source/script.cpp
@@ -1112,6 +1112,43 @@ int CEXEBuild::doCommand(int which_token, LineParser &line)
     case TOK_P_MACROEND:
       ERROR_MSG(_T("!macroend: no macro currently open.\n"));
     return PS_ERROR;
+    case TOK_P_MACROUNDEF:
+      {
+        const TCHAR* mname=line.gettoken_str(1);
+        if (!mname[0]) PRINTHELP()
+        TCHAR *t=(TCHAR *)m_macros.get(), *mbeg, *mend=0, *mbufb=t;
+        while (t && *t)
+        {
+          const bool foundit = !_tcsicmp((mbeg=t),mname);
+          t+=_tcslen(t)+1;
+
+          // advance over parameters
+          while (*t) t+=_tcslen(t)+1;
+          t++;
+
+          // advance over data
+          while (*t) t+=_tcslen(t)+1;
+          if (foundit)
+          {
+            mend=t;
+            break;
+          }
+          if (t-mbufb >= m_macros.getlen()-1)
+            break;
+          t++;
+        }
+        if (!mend)
+        {
+          ERROR_MSG(_T("!macroundef: \"%s\" does not exist!\n"),mname);
+          return PS_ERROR;
+        }
+        const unsigned int mcb=mend-mbeg, mbufcb=m_macros.getlen();
+        memmove(mbeg,mend+1,mbufcb-(mcb+(mbeg-mbufb)));
+        m_macros.resize(mbufcb-(mcb+1));
+
+        SCRIPT_MSG(_T("!macroundef: %s\n"),mname);
+      }
+    return PS_OK;
     case TOK_P_INSERTMACRO:
       {
         if (!line.gettoken_str(1)[0]) PRINTHELP()
diff --git a/Source/tokens.cpp b/Source/tokens.cpp
index aa20fcd2..4c398fea 100644
--- a/Source/tokens.cpp
+++ b/Source/tokens.cpp
@@ -262,6 +262,7 @@ static tokenType tokenlist[TOK__LAST] =
 
 {TOK_P_MACRO,_T("!macro"),1,-1,_T("macroname [parms ...]"),TP_ALL},
 {TOK_P_MACROEND,_T("!macroend"),0,0,_T(""),TP_ALL},
+{TOK_P_MACROUNDEF,_T("!macroundef"),1,0,_T("macroname"),TP_ALL},
 {TOK_P_INSERTMACRO,_T("!insertmacro"),1,-1,_T("macroname [parms ...]"),TP_ALL},
 {TOK_P_IFMACRODEF,_T("!ifmacrodef"),1,-1,_T("macro [| macro2 [& macro3 [...]]]"),TP_ALL},
 {TOK_P_IFMACRONDEF,_T("!ifmacrondef"),1,-1,_T("macro [| macro2 [& macro3 [...]]]"),TP_ALL},
diff --git a/Source/tokens.h b/Source/tokens.h
index f0b98173..2e0638c5 100644
--- a/Source/tokens.h
+++ b/Source/tokens.h
@@ -116,6 +116,7 @@ enum
 
   TOK_P_MACRO,
   TOK_P_MACROEND,
+  TOK_P_MACROUNDEF,
   TOK_P_INSERTMACRO,
   TOK_P_IFMACRODEF,
   TOK_P_IFMACRONDEF,