diff --git a/source/glest_game/type_instances/unit.cpp b/source/glest_game/type_instances/unit.cpp
index d2be5cd3..2eecd9ec 100644
--- a/source/glest_game/type_instances/unit.cpp
+++ b/source/glest_game/type_instances/unit.cpp
@@ -1,7 +1,7 @@
 // ==============================================================
 //	This file is part of Glest (www.glest.org)
 //
-//	Copyright (C) 2001-2008 Marti�o Figueroa
+//	Copyright (C) 2001-2008 Martiño Figueroa
 //
 //	You can redistribute this code and/or modify it under
 //	the terms of the GNU General Public License as published
@@ -500,6 +500,11 @@ unsigned int Unit::getCommandSize() const{
 	return commands.size();
 }
 
+#define deleteSingleCommand(command) {\
+	undoCommand(command);\
+	delete command;\
+}
+
 //give one command (clear, and push back)
 CommandResult Unit::giveCommand(Command *command, bool tryQueue){
 
@@ -515,7 +520,18 @@ CommandResult Unit::giveCommand(Command *command, bool tryQueue){
 
     SystemFlags::OutputDebug(SystemFlags::debugSystem,"In [%s::%s Line: %d]\n",__FILE__,__FUNCTION__,__LINE__);
 
-	if(command->getCommandType()->isQueuable(tryQueue)){
+    const int command_priority = command->getCommandType()->getPriority();
+
+	if(command->getCommandType()->isQueuable(tryQueue) && (commands.empty() || (command_priority >= commands.back()->getCommandType()->getPriority()))){
+		//Delete all lower-prioirty commands
+		for (list<Command*>::iterator i = commands.begin(); i != commands.end();) {
+			if ((*i)->getCommandType()->getPriority() < command_priority) {
+				deleteSingleCommand(*i);
+				i = commands.erase(i);
+			} else {
+				++i;
+			}
+		}
 		//cancel current command if it is not queuable
 		SystemFlags::OutputDebug(SystemFlags::debugSystem,"In [%s::%s Line: %d]\n",__FILE__,__FUNCTION__,__LINE__);
 
diff --git a/source/glest_game/types/command_type.h b/source/glest_game/types/command_type.h
index f40e759d..b0528bbf 100644
--- a/source/glest_game/types/command_type.h
+++ b/source/glest_game/types/command_type.h
@@ -88,6 +88,8 @@ public:
 		Queueability q = isQueuable();
 		return (q != qNever) && (q != qOnlyLast);
 	}
+	//Priority: commands of higher priority will cancel commands of lower priority
+	virtual int getPriority() const {return 0;}
 
     //get
     CommandClass getClass() const;
@@ -110,6 +112,7 @@ public:
     virtual string getDesc(const TotalUpgrade *totalUpgrade) const;
 	virtual string toString() const;
 	virtual Queueability isQueuable() const						{return qNever;}
+	virtual int getPriority() const							{return 100000;}
     //get
 	const StopSkillType *getStopSkillType() const	{return stopSkillType;};
 };
@@ -151,6 +154,7 @@ public:
     virtual string getDesc(const TotalUpgrade *totalUpgrade) const;
 	virtual string toString() const;
 
+
     //get
 	const MoveSkillType * getMoveSkillType() const			{return moveSkillType;}
 	const AttackSkillType * getAttackSkillType() const		{return attackSkillType;}
@@ -286,6 +290,7 @@ public:
 	virtual string toString() const;
 	virtual const ProducibleType *getProduced() const;
 	virtual Queueability isQueuable() const						{return qAlways;}
+	virtual int getPriority() const 						{return 5;} //higher priority to cancel attack
 
     //get
 	const ProduceSkillType *getProduceSkillType() const	{return produceSkillType;}
@@ -311,6 +316,7 @@ public:
 	virtual string getReqDesc() const;
 	virtual const ProducibleType *getProduced() const;
 	virtual Queueability isQueuable() const						{return qAlways;}
+	virtual int getPriority() const 						{return 5;} //higher priority to cancel attack (and same as Build)
 
     //get
 	const UpgradeSkillType *getUpgradeSkillType() const		{return upgradeSkillType;}