diff --git a/ChangeLog b/ChangeLog
index 3bbf572d8..3342bfba3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,7 +7,9 @@ represents a feature release, and the Z represents a patch.
 
 ------ current release ---------------------------
 
-1.5.0 (?/?/?)
+1.5.0 (?/?/2008)
+  + "task undo" can now retract a "task done" command, provided no reports
+    have been run (and therefore TDB::gc run)
 
 ------ old releases ------------------------------
 
diff --git a/html/task.html b/html/task.html
index 84f28544e..b536566dd 100644
--- a/html/task.html
+++ b/html/task.html
@@ -94,7 +94,8 @@
 
                 <h4>New in version 1.5.0 (?/?/?)</h4>
                 <ul>
-                  <li>
+                  <li>"task undo" can now retract a "task done" command, provided no
+                      reports have been run.
                 </ul>
 
                 <p>
diff --git a/src/command.cpp b/src/command.cpp
index 5344a4037..91a3053f2 100644
--- a/src/command.cpp
+++ b/src/command.cpp
@@ -203,6 +203,49 @@ void handleUndelete (TDB& tdb, T& task, Config& conf)
             << "command is run immediately after the errant delete command." << std::endl;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// If a task is done, but is still in the pending file, then it may be undone
+// simply by changing it's status.
+void handleUndo (TDB& tdb, T& task, Config& conf)
+{
+  std::vector <T> all;
+  tdb.allPendingT (all);
+
+  int id = task.getId ();
+  std::vector <T>::iterator it;
+  for (it = all.begin (); it != all.end (); ++it)
+  {
+    if (it->getId () == id)
+    {
+      if (it->getStatus () == T::completed)
+      {
+        if (it->getAttribute ("recur") != "")
+        {
+          std::cout << "Task does not support 'undo' for recurring tasks." << std::endl;
+          return;
+        }
+
+        T restored (*it);
+        restored.setStatus (T::pending);
+        restored.removeAttribute ("end");
+        tdb.modifyT (restored);
+
+        std::cout << "Task " << id << " successfully undone." << std::endl;
+        return;
+      }
+      else
+      {
+        std::cout << "Task " << id << " is not done - therefore cannot be undone." << std::endl;
+        return;
+      }
+    }
+  }
+
+  std::cout << "Task " << id
+            << " not found - tasks can only be reliably undone if the undo" << std::endl
+            << "command is run immediately after the errant done command." << std::endl;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 void handleVersion (Config& conf)
 {
diff --git a/src/parse.cpp b/src/parse.cpp
index 770c2b2f0..a8bba1e57 100644
--- a/src/parse.cpp
+++ b/src/parse.cpp
@@ -141,6 +141,7 @@ static const char* commands[] =
   "summary",
   "tags",
   "undelete",
+  "undo",
   "usage",
   "version",
   "",
diff --git a/src/task.cpp b/src/task.cpp
index 0d3f6c7f5..cc192e18e 100644
--- a/src/task.cpp
+++ b/src/task.cpp
@@ -125,6 +125,10 @@ static void shortUsage (Config& conf)
   table.addCell (row, 1, "task done ID");
   table.addCell (row, 2, "Marks the specified task as completed");
 
+  row = table.addRow ();
+  table.addCell (row, 1, "task undo ID");
+  table.addCell (row, 2, "Marks the specified done task as pending, provided a report has not yet been run");
+
   row = table.addRow ();
   table.addCell (row, 1, "task projects");
   table.addCell (row, 2, "Shows a list of all project names used, and how many tasks are in each");
@@ -316,6 +320,7 @@ int main (int argc, char** argv)
     else if (command == "delete")             handleDelete         (tdb, task, conf);
     else if (command == "start")              handleStart          (tdb, task, conf);
     else if (command == "done")               handleDone           (tdb, task, conf);
+    else if (command == "undo")               handleUndo           (tdb, task, conf);
     else if (command == "export")             handleExport         (tdb, task, conf);
     else if (command == "version")            handleVersion        (           conf);
     else if (command == "summary")            handleReportSummary  (tdb, task, conf);
diff --git a/src/task.h b/src/task.h
index 4a8dc78fd..ced6b3c18 100644
--- a/src/task.h
+++ b/src/task.h
@@ -76,6 +76,7 @@ void handleExport (TDB&, T&, Config&);
 void handleDelete (TDB&, T&, Config&);
 void handleStart (TDB&, T&, Config&);
 void handleDone (TDB&, T&, Config&);
+void handleUndo (TDB&, T&, Config&);
 void handleModify (TDB&, T&, Config&);
 void handleColor (Config&);