diff --git a/Tactical/Drugs And Alcohol.cpp b/Tactical/Drugs And Alcohol.cpp
index d664dce6..c4dacc42 100644
--- a/Tactical/Drugs And Alcohol.cpp	
+++ b/Tactical/Drugs And Alcohol.cpp	
@@ -329,7 +329,7 @@ BOOLEAN DoesMercHaveDisability( SOLDIERTYPE *pSoldier, UINT8 aVal )
 		if ( pSoldier->newdrugs.drugdisability == aVal )
 			return TRUE;
 
-		if ( pSoldier->usDisabilityFlagMask & ( 1 << aVal ) )
+		if ( pSoldier->usDisabilityFlagMask & ( 1 << (aVal - 1) ) )
 			return TRUE;
 	}
 
diff --git a/Tactical/Soldier Control.cpp b/Tactical/Soldier Control.cpp
index cf5b8ce3..61950133 100644
--- a/Tactical/Soldier Control.cpp	
+++ b/Tactical/Soldier Control.cpp	
@@ -19316,7 +19316,7 @@ void	SOLDIERTYPE::AnnounceDisease( UINT8 aDisease )
 
 void	SOLDIERTYPE::AddDisability( UINT8 aDisability )
 {
-	this->usDisabilityFlagMask |= ( 1 << aDisability );
+	this->usDisabilityFlagMask |= ( 1 << (aDisability - 1 ) );
 }
 
 // do we have any disease? fDiagnosedOnly: check for wether we know of this infection fHealableOnly: check wether it can be healed