diff --git a/README.md b/README.md
index 0ad3def..c067222 100644
--- a/README.md
+++ b/README.md
@@ -761,6 +761,23 @@ $point = $this->collection
     ->findOne();
 ```
 
+Search documents with points (stored as legacy coordinates) within polygon:
+```php
+<?php
+$point = $this->collection
+    ->find()
+    ->withinPolygon(
+        'point',
+        array(
+            array(0, 0), 
+            array(0, 10), 
+            array(10, 10),
+            array(10, 0),
+        )
+    )
+    ->findOne();
+```
+
 Pagination
 ----------
 
diff --git a/src/Expression.php b/src/Expression.php
index 05c8cbb..adb83cc 100644
--- a/src/Expression.php
+++ b/src/Expression.php
@@ -539,7 +539,7 @@ public function withinCircleSpherical($field, $longitude, $latitude, $radiusInRa
      * Based on grid coordinates and does not query for GeoJSON shapes.
      *
      * Use planar geometry, so 2d index may be used but not required
-     * 
+     *
      * @param string $field
      * @param array $bottomLeftCoordinate Bottom left coordinate of box
      * @param array $upperRightCoordinate Upper right coordinate of box
@@ -559,6 +559,29 @@ public function withinBox($field, array $bottomLeftCoordinate, array $upperRight
         return $this;
     }
 
+    /**
+     * Return documents that are within the polygon, according
+     * to their point-based location data.
+     *
+     * Based on grid coordinates and does not query for GeoJSON shapes.
+     *
+     * Use planar geometry, so 2d index may be used but not required
+     *
+     * @param string $field
+     * @param array $points array of coordinates
+     * @return \Sokil\Mongo\Expression
+     */
+    public function withinPolygon($field, array $points)
+    {
+        $this->where($field, array(
+            '$geoWithin' => array(
+                '$polygon' => $points,
+            ),
+        ));
+
+        return $this;
+    }
+
     public function toArray()
     {
         return $this->_expression;
diff --git a/tests/DocumentGeoTest.php b/tests/DocumentGeoTest.php
index e0d5e2e..e8a0cef 100644
--- a/tests/DocumentGeoTest.php
+++ b/tests/DocumentGeoTest.php
@@ -699,4 +699,37 @@ public function testExpressionWithinBox()
         $this->assertNotEmpty($point);
         $this->assertEquals($point1Id, $point->getId());
     }
+
+    public function testExpressionWithinPolygon()
+    {
+        $this->collection->ensure2dIndex('point');
+
+        $point1Id = $this->collection
+            ->createDocument()
+            ->setLegacyPoint('point', 5, 4)
+            ->save()
+            ->getId();
+
+        $point2Id = $this->collection
+            ->createDocument()
+            ->setLegacyPoint('point', 50, 40)
+            ->save()
+            ->getId();
+
+        $point = $this->collection
+            ->find()
+            ->withinPolygon(
+                'point',
+                array(
+                    array(0, 0),
+                    array(0, 10),
+                    array(10, 10),
+                    array(10, 0),
+                )
+            )
+            ->findOne();
+
+        $this->assertNotEmpty($point);
+        $this->assertEquals($point1Id, $point->getId());
+    }
 }
\ No newline at end of file