diff --git a/lib/mobility/active_record/uniqueness_validator.rb b/lib/mobility/active_record/uniqueness_validator.rb
index 14a47f610..e035628e5 100644
--- a/lib/mobility/active_record/uniqueness_validator.rb
+++ b/lib/mobility/active_record/uniqueness_validator.rb
@@ -26,12 +26,11 @@ def validate_each(record, attribute, value)
         klass = record.class
 
         if (([*options[:scope]] + [attribute]).map(&:to_s) & klass.mobility_attributes).present?
-          warn %{
-WARNING: The Mobility uniqueness validator for translated attributes does not
-support case-insensitive validation. This option will be ignored for: #{attribute}
-} if options[:case_sensitive] == false
           return unless value.present?
-          relation = klass.send(Mobility.query_method).where(attribute => value)
+          relation = klass.send(Mobility.query_method) do |m|
+            node = m.__send__(attribute)
+            options[:case_sensitive] == false ? node.lower.eq(value.downcase) : node.eq(value)
+          end
           relation = relation.where.not(klass.primary_key => record.id) if record.persisted?
           relation = mobility_scope_relation(record, relation)
           relation = relation.merge(options[:conditions]) if options[:conditions]
@@ -51,7 +50,9 @@ def validate_each(record, attribute, value)
 
       def mobility_scope_relation(record, relation)
         [*options[:scope]].inject(relation) do |scoped_relation, scope_item|
-          scoped_relation.where(scope_item => record.send(scope_item))
+          scoped_relation.send(Mobility.query_method) do |m|
+            m.__send__(scope_item).eq(record.send(scope_item))
+          end
         end
       end
     end
diff --git a/spec/mobility/active_record_spec.rb b/spec/mobility/active_record_spec.rb
index dc3a1a5dd..8a1a52dfc 100644
--- a/spec/mobility/active_record_spec.rb
+++ b/spec/mobility/active_record_spec.rb
@@ -15,45 +15,4 @@ def translated_attribute_names; end
       expect(Article.new.translated_attribute_names).to eq(["foo"])
     end
   end
-
-  describe "uniqueness validation" do
-    before do
-      opts = uniqueness_opts
-      Article.class_eval do
-        extend Mobility
-        translates :title, backend: :null
-        validates :title, uniqueness: opts
-      end
-    end
-    let(:article) do
-      Article.new
-    end
-
-    context "case_sensitive = false" do
-      let(:uniqueness_opts) { { case_sensitive: false } }
-
-      it "ignores option and emits warning" do
-        expect { expect(article.valid?).to eq(true) }.to output(
-          /#{%{
-WARNING: The Mobility uniqueness validator for translated attributes does not
-support case-insensitive validation. This option will be ignored for: title}}/).to_stderr
-      end
-    end
-
-    context "case_sensitive = nil" do
-      let(:uniqueness_opts) { { } }
-
-      it "does not emit warning" do
-        expect { expect(article.valid?).to eq(true) }.not_to output.to_stderr
-      end
-    end
-
-    context "case_sensitive = true" do
-      let(:uniqueness_opts) { { case_sensitive: true } }
-
-      it "does not emit warning" do
-        expect { expect(article.valid?).to eq(true) }.not_to output.to_stderr
-      end
-    end
-  end
 end if Mobility::Loaded::ActiveRecord