diff --git a/app/services/bulk_upload/lettings/year2023/row_parser.rb b/app/services/bulk_upload/lettings/year2023/row_parser.rb
index 2fc61921f..921e42e89 100644
--- a/app/services/bulk_upload/lettings/year2023/row_parser.rb
+++ b/app/services/bulk_upload/lettings/year2023/row_parser.rb
@@ -328,6 +328,9 @@ class BulkUpload::Lettings::Year2023::RowParser
   validate :validate_location_exists
   validate :validate_location_data_given
 
+  validate :validate_created_by_exists
+  validate :validate_created_by_related
+
   def self.question_for_field(field)
     QUESTIONS[field]
   end
@@ -385,6 +388,28 @@ class BulkUpload::Lettings::Year2023::RowParser
 
 private
 
+  def validate_created_by_exists
+    return if field_3.blank?
+
+    unless created_by
+      block_log_creation!
+      errors.add(:field_3, "User with the specified email could not be found")
+    end
+  end
+
+  def validate_created_by_related
+    return unless created_by
+
+    unless (created_by.organisation == owning_organisation) || (created_by.organisation == managing_organisation)
+      block_log_creation!
+      errors.add(:field_3, "User must be related to owning organisation or managing organisation")
+    end
+  end
+
+  def created_by
+    @created_by ||= User.find_by(email: field_3)
+  end
+
   def validate_needs_type_present
     if field_4.blank?
       errors.add(:field_4, I18n.t("validations.not_answered", question: "needs type"))
@@ -630,7 +655,7 @@ private
       renewal: [:field_6],
       scheme: %i[field_16],
       location: %i[field_17],
-      created_by: [],
+      created_by: [:field_3],
       needstype: [:field_4],
       rent_type: %i[field_5 field_10 field_11],
       startdate: %i[field_7 field_8 field_9],
@@ -796,7 +821,7 @@ private
     attributes["renewal"] = renewal
     attributes["scheme"] = scheme
     attributes["location"] = location
-    attributes["created_by"] = bulk_upload.user
+    attributes["created_by"] = created_by || bulk_upload.user
     attributes["needstype"] = field_4
     attributes["rent_type"] = rent_type
     attributes["startdate"] = startdate
diff --git a/spec/services/bulk_upload/lettings/year2023/row_parser_spec.rb b/spec/services/bulk_upload/lettings/year2023/row_parser_spec.rb
index a7dc629c0..f32876335 100644
--- a/spec/services/bulk_upload/lettings/year2023/row_parser_spec.rb
+++ b/spec/services/bulk_upload/lettings/year2023/row_parser_spec.rb
@@ -242,6 +242,62 @@ RSpec.describe BulkUpload::Lettings::Year2023::RowParser do
       end
     end
 
+    describe "#field_3" do # created_by
+      context "when blank" do
+        let(:attributes) { { bulk_upload:, field_3: "" } }
+
+        it "is permitted" do
+          expect(parser.errors[:field_3]).to be_blank
+        end
+      end
+
+      context "when user could not be found" do
+        let(:attributes) { { bulk_upload:, field_3: "idonotexist@example.com" } }
+
+        it "is not permitted" do
+          expect(parser.errors[:field_3]).to be_present
+        end
+
+        it "blocks log creation" do
+          expect(parser).to be_block_log_creation
+        end
+      end
+
+      context "when an unaffiliated user" do
+        let(:other_user) { create(:user) }
+
+        let(:attributes) { { bulk_upload:, field_1: owning_org.old_visible_id, field_3: other_user.email, field_2: managing_org.old_visible_id } }
+
+        it "is not permitted" do
+          expect(parser.errors[:field_3]).to be_present
+        end
+
+        it "blocks log creation" do
+          expect(parser).to be_block_log_creation
+        end
+      end
+
+      context "when an user part of owning org" do
+        let(:other_user) { create(:user, organisation: owning_org) }
+
+        let(:attributes) { { bulk_upload:, field_1: owning_org.old_visible_id, field_3: other_user.email, field_2: managing_org.old_visible_id } }
+
+        it "is permitted" do
+          expect(parser.errors[:field_3]).to be_blank
+        end
+      end
+
+      context "when an user part of managing org" do
+        let(:other_user) { create(:user, organisation: managing_org) }
+
+        let(:attributes) { { bulk_upload:, field_1: owning_org.old_visible_id, field_3: other_user.email, field_2: managing_org.old_visible_id } }
+
+        it "is permitted" do
+          expect(parser.errors[:field_3]).to be_blank
+        end
+      end
+    end
+
     describe "#field_5" do
       context "when null" do
         let(:attributes) { { bulk_upload:, field_5: nil, field_15: "1" } }
@@ -767,6 +823,26 @@ RSpec.describe BulkUpload::Lettings::Year2023::RowParser do
   end
 
   describe "#log" do
+    describe "#created_by" do
+      context "when blank" do
+        let(:attributes) { setup_section_params }
+
+        it "takes the user that is uploading" do
+          expect(parser.log.created_by).to eql(bulk_upload.user)
+        end
+      end
+
+      context "when email specified" do
+        let(:other_user) { create(:user, organisation: owning_org) }
+
+        let(:attributes) { setup_section_params.merge(field_3: other_user.email) }
+
+        it "sets to user with specified email" do
+          expect(parser.log.created_by).to eql(other_user)
+        end
+      end
+    end
+
     describe "#uprn" do
       let(:attributes) { { bulk_upload:, field_18: "100023336956" } }