diff --git a/src/common/ctrlsub.cpp b/src/common/ctrlsub.cpp
index 68d4b1a591..388af3e6ff 100644
--- a/src/common/ctrlsub.cpp
+++ b/src/common/ctrlsub.cpp
@@ -165,6 +165,8 @@ void wxItemContainer::SetClientObject(unsigned int n, wxClientData *data)
     wxASSERT_MSG( !HasClientUntypedData(),
                   wxT("can't have both object and void client data") );
 
+    wxCHECK_RET( IsValid(n), "Invalid index passed to SetClientObject()" );
+
     if ( HasClientObjectData() )
     {
         wxClientData * clientDataOld
@@ -188,6 +190,9 @@ wxClientData *wxItemContainer::GetClientObject(unsigned int n) const
     wxCHECK_MSG( HasClientObjectData(), NULL,
                   wxT("this window doesn't have object client data") );
 
+    wxCHECK_MSG( IsValid(n), NULL,
+                 "Invalid index passed to GetClientObject()" );
+
     return static_cast<wxClientData *>(DoGetItemClientData(n));
 }
 
@@ -214,6 +219,8 @@ void wxItemContainer::SetClientData(unsigned int n, void *data)
     wxASSERT_MSG( HasClientUntypedData(),
                   wxT("can't have both object and void client data") );
 
+    wxCHECK_RET( IsValid(n), "Invalid index passed to SetClientData()" );
+
     DoSetItemClientData(n, data);
 }
 
@@ -222,6 +229,9 @@ void *wxItemContainer::GetClientData(unsigned int n) const
     wxCHECK_MSG( HasClientUntypedData(), NULL,
                   wxT("this window doesn't have void client data") );
 
+    wxCHECK_MSG( IsValid(n), NULL,
+                 "Invalid index passed to GetClientData()" );
+
     return DoGetItemClientData(n);
 }
 
diff --git a/src/gtk/listbox.cpp b/src/gtk/listbox.cpp
index 06c62c2ff5..9a406184bd 100644
--- a/src/gtk/listbox.cpp
+++ b/src/gtk/listbox.cpp
@@ -578,9 +578,6 @@ void wxListBox::GTKSetItem(GtkTreeIter& iter, const GtkTreeEntry *entry)
 
 void* wxListBox::DoGetItemClientData(unsigned int n) const
 {
-    wxCHECK_MSG( IsValid(n), NULL,
-                 wxT("Invalid index passed to GetItemClientData") );
-
     wxGtkObject<GtkTreeEntry> entry(GTKGetEntry(n));
     wxCHECK_MSG(entry, NULL, wxT("could not get entry"));
 
@@ -589,9 +586,6 @@ void* wxListBox::DoGetItemClientData(unsigned int n) const
 
 void wxListBox::DoSetItemClientData(unsigned int n, void* clientData)
 {
-    wxCHECK_RET( IsValid(n),
-                 wxT("Invalid index passed to SetItemClientData") );
-
     wxGtkObject<GtkTreeEntry> entry(GTKGetEntry(n));
     wxCHECK_RET(entry, wxT("could not get entry"));
 
diff --git a/src/msw/listbox.cpp b/src/msw/listbox.cpp
index 69281add2b..69565096f7 100644
--- a/src/msw/listbox.cpp
+++ b/src/msw/listbox.cpp
@@ -306,17 +306,11 @@ bool wxListBox::IsSelected(int N) const
 
 void *wxListBox::DoGetItemClientData(unsigned int n) const
 {
-    wxCHECK_MSG( IsValid(n), NULL,
-                 wxT("invalid index in wxListBox::GetClientData") );
-
     return (void *)SendMessage(GetHwnd(), LB_GETITEMDATA, n, 0);
 }
 
 void wxListBox::DoSetItemClientData(unsigned int n, void *clientData)
 {
-    wxCHECK_RET( IsValid(n),
-                 wxT("invalid index in wxListBox::SetClientData") );
-
     if ( ListBox_SetItemData(GetHwnd(), n, clientData) == LB_ERR )
     {
         wxLogDebug(wxT("LB_SETITEMDATA failed"));
diff --git a/src/osx/choice_osx.cpp b/src/osx/choice_osx.cpp
index e3d6cdab48..28af5cdf2c 100644
--- a/src/osx/choice_osx.cpp
+++ b/src/osx/choice_osx.cpp
@@ -219,15 +219,11 @@ wxString wxChoice::GetString(unsigned int n) const
 // ----------------------------------------------------------------------------
 void wxChoice::DoSetItemClientData(unsigned int n, void* clientData)
 {
-    wxCHECK_RET( IsValid(n), wxT("wxChoice::DoSetItemClientData: invalid index") );
-
     m_datas[n] = (char*)clientData ;
 }
 
 void * wxChoice::DoGetItemClientData(unsigned int n) const
 {
-    wxCHECK_MSG( IsValid(n), NULL, wxT("wxChoice::DoGetClientData: invalid index") );
-
     return (void *)m_datas[n];
 }
 
diff --git a/src/osx/combobox_osx.cpp b/src/osx/combobox_osx.cpp
index 8e814f8eba..bf092f3772 100644
--- a/src/osx/combobox_osx.cpp
+++ b/src/osx/combobox_osx.cpp
@@ -120,15 +120,11 @@ int wxComboBox::DoInsertItems(const wxArrayStringsAdapter& items,
 // ----------------------------------------------------------------------------
 void wxComboBox::DoSetItemClientData(unsigned int n, void* clientData)
 {
-    wxCHECK_RET( IsValid(n), "invalid index" );
-
     m_datas[n] = (char*)clientData ;
 }
 
 void * wxComboBox::DoGetItemClientData(unsigned int n) const
 {
-    wxCHECK_MSG( IsValid(n), NULL, "invalid index" );
-
     return (void *)m_datas[n];
 }
 
diff --git a/tests/controls/itemcontainertest.cpp b/tests/controls/itemcontainertest.cpp
index ab8b9807fb..c470749098 100644
--- a/tests/controls/itemcontainertest.cpp
+++ b/tests/controls/itemcontainertest.cpp
@@ -170,6 +170,9 @@ void ItemContainerTestCase::ClientData()
 
     CPPUNIT_ASSERT_EQUAL(static_cast<wxClientData*>(item2data),
                          container->GetClientObject(2));
+
+    WX_ASSERT_FAILS_WITH_ASSERT( container->SetClientObject(-1, item0data) );
+    WX_ASSERT_FAILS_WITH_ASSERT( container->SetClientObject(12345, item0data) );
 }
 
 void ItemContainerTestCase::VoidData()
@@ -195,6 +198,9 @@ void ItemContainerTestCase::VoidData()
     container->Insert("item 2", 2, item2);
 
     CPPUNIT_ASSERT_EQUAL(item2, container->GetClientData(2));
+
+    WX_ASSERT_FAILS_WITH_ASSERT( container->SetClientData(-1, NULL) );
+    WX_ASSERT_FAILS_WITH_ASSERT( container->SetClientData(12345, NULL) );
 }
 
 void ItemContainerTestCase::Set()