diff --git a/association.go b/association.go
index 7f56c2d8..4bc7269f 100644
--- a/association.go
+++ b/association.go
@@ -86,10 +86,18 @@ func (association *Association) Replace(values ...interface{}) *Association {
 	scope := association.Scope
 	field := association.Field.Field
 
+	// get old primary keys
 	oldPrimaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, field.Interface())
+
+	// append new values
 	association.Field.Set(reflect.Zero(association.Field.Field.Type()))
 	association.Append(values...)
-	newPrimaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, field.Interface())
+
+	// get new primary keys
+	var newPrimaryKeys [][]interface{}
+	if len(values) > 0 {
+		newPrimaryKeys = association.getPrimaryKeys(relationship.AssociationForeignFieldNames, field.Interface())
+	}
 
 	var addedPrimaryKeys = [][]interface{}{}
 	for _, newKey := range newPrimaryKeys {
@@ -111,25 +119,49 @@ func (association *Association) Replace(values ...interface{}) *Association {
 
 	query := scope.NewDB()
 	var foreignKeyMap = map[string]interface{}{}
-	for idx, foreignKey := range relationship.ForeignDBNames {
-		foreignKeyMap[foreignKey] = nil
-		if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
-			query = query.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+
+	if relationship.Kind == "belongs_to" {
+		for idx, foreignKey := range relationship.AssociationForeignDBNames {
+			if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
+				query = query.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+			}
 		}
-	}
 
-	if len(addedPrimaryKeys) > 0 {
-		sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(addedPrimaryKeys))
-		query = query.Where(sql, toQueryValues(addedPrimaryKeys)...)
-	}
+		for _, foreignKey := range relationship.ForeignDBNames {
+			foreignKeyMap[foreignKey] = nil
+		}
 
-	if relationship.Kind == "many_to_many" {
-		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, query, relationship))
-	} else if relationship.Kind == "belongs_to" {
-		association.setErr(query.Model(scope.Value).UpdateColumn(foreignKeyMap).Error)
-	} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
-		fieldValue := reflect.New(association.Field.Field.Type()).Interface()
-		association.setErr(query.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		if len(addedPrimaryKeys) > 0 {
+			sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(addedPrimaryKeys))
+			query = query.Where(sql, toQueryValues(addedPrimaryKeys)...)
+		}
+
+		modelValue := scope.Value
+		// if replacing with a new value, don't reset current foreign key
+		// if clearing foreign value, then reset the foreign key to null
+		if len(values) > 0 {
+			modelValue = reflect.New(scope.GetModelStruct().ModelType).Interface()
+		}
+		association.setErr(query.Model(modelValue).UpdateColumn(foreignKeyMap).Error)
+	} else {
+		for idx, foreignKey := range relationship.ForeignDBNames {
+			foreignKeyMap[foreignKey] = nil
+			if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
+				query = query.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+			}
+		}
+
+		if len(addedPrimaryKeys) > 0 {
+			sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(addedPrimaryKeys))
+			query = query.Where(sql, toQueryValues(addedPrimaryKeys)...)
+		}
+
+		if relationship.Kind == "many_to_many" {
+			association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, query, relationship))
+		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
+			fieldValue := reflect.New(association.Field.Field.Type()).Interface()
+			association.setErr(query.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		}
 	}
 	return association
 }
@@ -184,8 +216,8 @@ func (association *Association) Delete(values ...interface{}) *Association {
 			}
 			primaryKeys := association.getPrimaryKeys(relationship.AssociationForeignFieldNames, values...)
 			sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys))
-			association.setErr(query.Model(scope.Value).Where(sql, toQueryValues(primaryKeys)...).UpdateColumn(foreignKeyMap).Error)
 
+			association.setErr(query.Model(scope.Value).Where(sql, toQueryValues(primaryKeys)...).UpdateColumn(foreignKeyMap).Error)
 		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
 			var foreignKeyMap = map[string]interface{}{}
 			for _, foreignKey := range relationship.ForeignDBNames {
@@ -250,8 +282,7 @@ func (association *Association) Count() int {
 	return count
 }
 
-func (association *Association) getPrimaryKeys(columns []string, values ...interface{}) [][]interface{} {
-	results := [][]interface{}{}
+func (association *Association) getPrimaryKeys(columns []string, values ...interface{}) (results [][]interface{}) {
 	scope := association.Scope
 
 	for _, value := range values {
@@ -283,7 +314,8 @@ func (association *Association) getPrimaryKeys(columns []string, values ...inter
 			results = append(results, primaryKeys)
 		}
 	}
-	return results
+
+	return
 }
 
 func toQueryMarks(primaryValues [][]interface{}) string {
diff --git a/association_test.go b/association_test.go
index c094b81e..92854d89 100644
--- a/association_test.go
+++ b/association_test.go
@@ -106,7 +106,7 @@ func TestBelongsTo(t *testing.T) {
 		t.Errorf("Should find category after append")
 	}
 
-	DB.Model(&post).Debug().Association("Category").Clear()
+	DB.Model(&post).Association("Category").Clear()
 
 	if !DB.Model(&post).Related(&Category{}).RecordNotFound() {
 		t.Errorf("Should not find any category after Clear")
@@ -179,7 +179,7 @@ func TestHasMany(t *testing.T) {
 	}
 
 	// Replace
-	DB.Model(&Post{Id: 999}).Debug().Association("Comments").Replace()
+	DB.Model(&Post{Id: 999}).Association("Comments").Replace()
 
 	var comments4 []Comment
 	DB.Model(&post).Related(&comments4)