Index: library/Zend/Paginator.php
===================================================================
--- library/Zend/Paginator.php	(revision 22291)
+++ library/Zend/Paginator.php	(working copy)
@@ -706,8 +706,10 @@
     public function setItemCountPerPage($itemCountPerPage)
     {
         $this->_itemCountPerPage = (integer) $itemCountPerPage;
-        if ($this->_itemCountPerPage < 1) {
+        if ($this->_itemCountPerPage == 0) {
             $this->_itemCountPerPage = $this->getItemCountPerPage();
+        } else if ($this->_itemCountPerPage < 0) {
+            $this->_itemCountPerPage = $this->getTotalItemCount();
         }
         $this->_pageCount        = $this->_calculatePageCount();
         $this->_currentItems     = null;
Index: tests/Zend/PaginatorTest.php
===================================================================
--- tests/Zend/PaginatorTest.php	(revision 22291)
+++ tests/Zend/PaginatorTest.php	(working copy)
@@ -516,6 +516,8 @@
         $this->assertEquals(15, $this->_paginator->getItemCountPerPage());
         $this->_paginator->setItemCountPerPage(0);
         $this->assertEquals(10, $this->_paginator->getItemCountPerPage());
+        $this->_paginator->setItemCountPerPage(-1);
+        $this->assertEquals(101, $this->_paginator->getItemCountPerPage());
         $this->_paginator->setItemCountPerPage(10);
     }