diff --git a/lib/mongoid-avro.rb b/lib/mongoid-avro.rb
index 2587859..5bc1af9 100644
--- a/lib/mongoid-avro.rb
+++ b/lib/mongoid-avro.rb
@@ -114,7 +114,12 @@ def convert_to_fields(klass, optional:)
 
       def convert_to_avro_format(type: , optional: true)
         case type.to_s
-        when "String", "Symbol", "BSON::Decimal128" then "string"
+        when "String", "Symbol" then "string"
+        when "BSON::Decimal128"
+          {
+            "type": "string",
+            "logicalType": "decimal"
+          }
         when "Integer" then "int"
         when "Float" then "double"
         when "BigDecimal" then "decimal"
diff --git a/spec/mongoid_avro_spec.rb b/spec/mongoid_avro_spec.rb
index b0f8b35..8e025d3 100644
--- a/spec/mongoid_avro_spec.rb
+++ b/spec/mongoid_avro_spec.rb
@@ -65,7 +65,12 @@ def get_field_by_name(fields, name)
       let(:field_name) { "decimal128" }
 
       it "convert decimal 128 to string" do
-        expect(field["type"]).to eq("string")
+        expect(field["type"]).to eq(
+          {
+            "type" => "string",
+            "logicalType" => "decimal"
+          }
+        )
       end
     end