diff --git a/src/index.js b/src/index.js
index 599bc3b..1647ba2 100644
--- a/src/index.js
+++ b/src/index.js
@@ -159,10 +159,13 @@ function loadWithRelations (items, resourceConfig, options) {
       })
     } else if (def.type === 'belongsTo' || (def.type === 'hasOne' && def.localKey)) {
       if (instance) {
-        task = this.find(resourceConfig.getResource(relationName), DSUtils.get(instance, def.localKey), __options).then(relatedItem => {
-          instance[def.localField] = relatedItem
-          return relatedItem
-        })
+        let id = DSUtils.get(instance, def.localKey)
+        if (id) {
+          task = this.find(resourceConfig.getResource(relationName), id, __options).then(relatedItem => {
+            instance[def.localField] = relatedItem
+            return relatedItem
+          })
+        }
       } else {
         task = this.findAll(resourceConfig.getResource(relationName), {
           where: {