diff --git a/shard.yml b/shard.yml
index ece90ff..269449d 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: active-model
-version: 4.3.1
+version: 4.3.2
 crystal: ">= 1.0.0"
 license: MIT
 
diff --git a/src/active-model/model.cr b/src/active-model/model.cr
index d5b230b..3360c53 100644
--- a/src/active-model/model.cr
+++ b/src/active-model/model.cr
@@ -352,7 +352,7 @@ abstract class ActiveModel::Model
     def assign_attributes(model : {{@type.name}})
       {% for name, opts in FIELDS %}
         {% if opts[:mass_assign] == true %}
-          self.{{name.id}} = model.{{name.id}} if model.{{name.id}}_assigned?
+          self.{{name.id}} = model.{{name.id}} if model.{{name.id}}_assigned? || model.{{name.id}}_present?
         {% end %}
       {% end %}
     end