diff --git a/plugins/FeedsProcessor.inc b/plugins/FeedsProcessor.inc
index e8b4b49..aaec9e2 100644
--- a/plugins/FeedsProcessor.inc
+++ b/plugins/FeedsProcessor.inc
@@ -667,12 +667,15 @@ abstract class FeedsProcessor extends FeedsPlugin {
     // Many mappers add to existing fields rather than replacing them. Hence we
     // need to clear target elements of each item before mapping in case we are
     // mapping on a prepopulated item such as an existing node.
-    foreach ($this->config['mappings'] as $mapping) {
-      if (isset($targets[$mapping['target']]['real_target'])) {
-        $target_item->{$targets[$mapping['target']]['real_target']} = NULL;
-      }
-      else {
-        $target_item->{$mapping['target']} = NULL;
+    // First, allow processors to disable "nulling" of values when empty.
+    if (empty($this->config['prevent_null_overwrite'])) {
+      foreach ($this->config['mappings'] as $mapping) {
+        if (isset($targets[$mapping['target']]['real_target'])) {
+          $target_item->{$targets[$mapping['target']]['real_target']} = NULL;
+        }
+        else {
+          $target_item->{$mapping['target']} = NULL;
+        }
       }
     }