diff --git a/client.h b/client.h
index fdc6655fd8..0e30000baf 100644
--- a/client.h
+++ b/client.h
@@ -72,6 +72,7 @@ class Client : public QObject, public KDecorationDefines
         QRect geometry() const;
         QSize size() const;
         QSize minSize() const;
+        QSize maxSize() const;
         QPoint pos() const;
         QRect rect() const;
         int x() const;
@@ -753,11 +754,6 @@ inline QSize Client::size() const
     return frame_geometry.size();
     }
 
-inline QSize Client::minSize() const
-    {
-    return QSize( xSizeHint.min_width, xSizeHint.min_height );
-    }
-
 inline QPoint Client::pos() const
     {
     return frame_geometry.topLeft();
diff --git a/geometry.cpp b/geometry.cpp
index 4215a06888..e7d9ac9cd3 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -27,6 +27,7 @@ License. See the file "COPYING" for the exact licensing terms.
 #include "placement.h"
 #include "notifications.h"
 #include "geometrytip.h"
+#include "rules.h"
 
 extern Time qt_x_time;
 
@@ -818,8 +819,8 @@ QSize Client::sizeForClientSize( const QSize& wsize, Sizemode mode ) const
 
     // basesize, minsize, maxsize, paspect and resizeinc have all values defined,
     // even if they're not set in flags - see getWmNormalHints()
-    QSize min_size( xSizeHint.min_width, xSizeHint.min_height );
-    QSize max_size( xSizeHint.max_width, xSizeHint.max_height );
+    QSize min_size = minSize();
+    QSize max_size = maxSize();
     if( decoration != NULL )
         {
         QSize decominsize = decoration->minimumSize();
@@ -1024,6 +1025,16 @@ void Client::getWmNormalHints()
     updateAllowedActions(); // affects isResizeable()
     }
 
+QSize Client::minSize() const
+    {
+    return rules()->checkMinSize( QSize( xSizeHint.min_width, xSizeHint.min_height ));
+    }
+
+QSize Client::maxSize() const
+    {
+    return rules()->checkMaxSize( QSize( xSizeHint.max_width, xSizeHint.max_height ));
+    }
+
 /*!
   Auxiliary function to inform the client about the current window
   configuration.
@@ -1287,10 +1298,9 @@ bool Client::isResizable() const
     if ( !isMovable() || !motif_may_resize || isSplash())
         return FALSE;
 
-    if ( ( xSizeHint.flags & PMaxSize) == 0 || (xSizeHint.flags & PMinSize ) == 0 )
-        return TRUE;
-    return ( xSizeHint.min_width < xSizeHint.max_width  ) ||
-          ( xSizeHint.min_height < xSizeHint.max_height  );
+    QSize min = minSize();
+    QSize max = maxSize();
+    return min.width() < max.width() || min.height() < max.height();
     }
 
 /*
@@ -1302,7 +1312,8 @@ bool Client::isMaximizable() const
         return TRUE;
     if( !isResizable() || isToolbar()) // SELI isToolbar() ?
         return false;
-    if( xSizeHint.max_height < 32767 || xSizeHint.max_width < 32767 ) // sizes are 16bit with X
+    QSize max = maxSize();
+    if( max.width() < 32767 || max.height() < 32767 ) // sizes are 16bit with X
         return false;
     return true;
     }
diff --git a/manage.cpp b/manage.cpp
index 26946bcb29..960bff219f 100644
--- a/manage.cpp
+++ b/manage.cpp
@@ -252,9 +252,11 @@ bool Client::manage( Window w, bool isMapped )
         }
 
     if (xSizeHint.flags & PMaxSize)
-        geom.setSize( geom.size().boundedTo( QSize(xSizeHint.max_width, xSizeHint.max_height ) ) );
+        geom.setSize( geom.size().boundedTo(
+            rules()->checkMaxSize( QSize(xSizeHint.max_width, xSizeHint.max_height ) ) ) );
     if (xSizeHint.flags & PMinSize)
-        geom.setSize( geom.size().expandedTo( QSize(xSizeHint.min_width, xSizeHint.min_height ) ) );
+        geom.setSize( geom.size().expandedTo(
+            rules()->checkMinSize( QSize(xSizeHint.min_width, xSizeHint.min_height ) ) ) );
 
     if( isMovable())
         {
diff --git a/rules.cpp b/rules.cpp
index 0ad9a53533..fd5390ebc6 100644
--- a/rules.cpp
+++ b/rules.cpp
@@ -30,6 +30,8 @@ WindowRules::WindowRules()
     , clientmachineregexp( false )
     , types( NET::AllTypesMask )
     , placementrule( DontCareRule )
+    , minsizerule( DontCareRule )
+    , maxsizerule( DontCareRule )
     , desktoprule( DontCareRule )
     , typerule( DontCareRule )
     , aboverule( DontCareRule )
@@ -53,6 +55,10 @@ WindowRules::WindowRules( KConfig& cfg )
     types = cfg.readUnsignedLongNumEntry( "types", NET::AllTypesMask );
     placement = Placement::policyFromString( cfg.readEntry( "placement" ), false );
     placementrule = readRule( cfg, "placementrule" );
+    minsize = cfg.readSizeEntry( "minsize" );
+    minsizerule = readRule( cfg, "minsizerule" );
+    maxsize = cfg.readSizeEntry( "maxsize" );
+    maxsizerule = readRule( cfg, "maxsizerule" );
     desktop = cfg.readNumEntry( "desktop" );
     desktoprule = readRule( cfg, "desktoprule" );
     type = readType( cfg, "type" );
@@ -107,6 +113,8 @@ void WindowRules::write( KConfig& cfg ) const
     WRITE_MATCH_STRING( clientmachine, (const char*) );
     WRITE_WITH_DEFAULT( types, NET::AllTypesMask );
     WRITE_SET_RULE( placement, Placement::policyToString );
+    WRITE_SET_RULE( minsize, );
+    WRITE_SET_RULE( maxsize, );
     WRITE_SET_RULE( desktop, );
     WRITE_SET_RULE( type, );
     WRITE_SET_RULE( above, );
@@ -203,6 +211,16 @@ Placement::Policy WindowRules::checkPlacement( Placement::Policy placement ) con
     return checkForceRule( placementrule ) ? this->placement : placement;
     }
 
+QSize WindowRules::checkMinSize( const QSize& s ) const
+    {
+    return checkForceRule( minsizerule ) ? this->minsize : s;
+    }
+
+QSize WindowRules::checkMaxSize( const QSize& s ) const
+    {
+    return checkForceRule( maxsizerule ) ? this->maxsize : s;
+    }
+
 int WindowRules::checkDesktop( int req_desktop, bool init ) const
     {
     // TODO chaining?
diff --git a/rules.h b/rules.h
index a873e0dd00..a68394b659 100644
--- a/rules.h
+++ b/rules.h
@@ -13,6 +13,7 @@ License. See the file "COPYING" for the exact licensing terms.
 
 #include <qstring.h>
 #include <netwm_def.h>
+#include <qrect.h>
 
 #include "placement.h"
 
@@ -41,6 +42,8 @@ class WindowRules
         void update( Client* );
         bool match( const Client* c ) const;
         Placement::Policy checkPlacement( Placement::Policy placement ) const;
+        QSize checkMinSize( const QSize& s ) const;
+        QSize checkMaxSize( const QSize& s ) const;
         int checkDesktop( int desktop, bool init = false ) const;
         NET::WindowType checkType( NET::WindowType type ) const;
         bool checkKeepAbove( bool above, bool init = false ) const;
@@ -65,6 +68,10 @@ class WindowRules
         unsigned long types; // types for matching
         Placement::Policy placement;
         SettingRule placementrule;
+        QSize minsize;
+        SettingRule minsizerule;
+        QSize maxsize;
+        SettingRule maxsizerule;
         int desktop;
         SettingRule desktoprule;
         NET::WindowType type; // type for setting