diff --git a/app/services/bulk_upload/sales/year2023/row_parser.rb b/app/services/bulk_upload/sales/year2023/row_parser.rb
index 11cd9f9a7..62598c5ad 100644
--- a/app/services/bulk_upload/sales/year2023/row_parser.rb
+++ b/app/services/bulk_upload/sales/year2023/row_parser.rb
@@ -823,6 +823,7 @@ private
     attributes["mortgageused"] = mortgageused
 
     attributes["uprn"] = field_19
+    attributes["uprn_known"] = field_19.present? ? 1 : 0
     attributes["address_line1"] = field_20
     attributes["address_line2"] = field_21
     attributes["town_or_city"] = field_22
diff --git a/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb b/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
index 8c5b899b9..3e6413be7 100644
--- a/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
+++ b/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
@@ -662,6 +662,24 @@ RSpec.describe BulkUpload::Sales::Year2023::RowParser do
       end
     end
 
+    describe "#uprn_known" do
+      context "when uprn known" do
+        let(:attributes) { setup_section_params.merge({ field_19: "100023336956" }) }
+
+        it "is correctly set" do
+          expect(parser.log.uprn_known).to be(1)
+        end
+      end
+
+      context "when uprn not known" do
+        let(:attributes) { setup_section_params.merge({ field_19: nil }) }
+
+        it "is correctly set" do
+          expect(parser.log.uprn_known).to be(0)
+        end
+      end
+    end
+
     describe "#address_line1" do
       let(:attributes) { setup_section_params.merge({ field_20: "some street" }) }