diff --git a/app/controllers/repp/v1/certificates_controller.rb b/app/controllers/repp/v1/certificates_controller.rb
index 632bff615..b4b7aeda5 100644
--- a/app/controllers/repp/v1/certificates_controller.rb
+++ b/app/controllers/repp/v1/certificates_controller.rb
@@ -19,11 +19,14 @@ module Repp
       desc 'Submit a new api user certificate signing request'
       def create
         @api_user = current_user.registrar.api_users.find(cert_params[:api_user_id])
-
         csr = decode_cert_params(cert_params[:csr])
 
-        @certificate = @api_user.certificates.build(csr: csr)
+        if csr.blank?
+          @certificate.errors.add(:base, I18n.t(:crt_or_csr_must_be_present))
+          return handle_non_epp_errors(@certificate)
+        end
 
+        @certificate = @api_user.certificates.build(csr: csr)
         if @certificate.save
           notify_admins
           render_success(data: { api_user: { id: @api_user.id } })
@@ -69,7 +72,6 @@ module Repp
 
       def decode_cert_params(csr_params)
         return if csr_params.blank?
-
         return nil if csr_params[:body] == 'invalid'
 
         begin
diff --git a/app/models/certificate.rb b/app/models/certificate.rb
index 6ff032c4b..62c0a0a2e 100644
--- a/app/models/certificate.rb
+++ b/app/models/certificate.rb
@@ -43,6 +43,23 @@ class Certificate < ApplicationRecord
     errors.add(:base, I18n.t(:invalid_csr_or_crt))
   end
 
+  validate :validate_csr_parameters, if: -> { new_record? && csr.present? && parsed_csr.present? }
+  def validate_csr_parameters
+    subject = parsed_csr.subject.to_s
+    common_name = subject.scan(%r{/CN=([^/]+)}).flatten.first
+    country = subject.scan(%r{/C=([^/]+)}).flatten.first
+
+    unless common_name == api_user.username
+      errors.add(:base, I18n.t(:csr_common_name_must_match_username))
+    end
+
+    if country.present? && api_user.registrar.address_country_code.present?
+      unless country == api_user.registrar.address_country_code
+        errors.add(:base, I18n.t(:csr_country_must_match_registrar_country))
+      end
+    end
+  end
+
   validate :assign_metadata, on: :create
   def assign_metadata
     return if errors.any?
diff --git a/config/locales/en.yml b/config/locales/en.yml
index fe98336f3..e7c32a745 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -706,3 +706,7 @@ en:
     errors:
       invalid_ca: "Invalid Certificate Authority for this interface"
       active_certificate_exists: "Active certificate already exists for this user and interface"
+
+  # Adding translation keys for certificate CSR validation
+  csr_common_name_must_match_username: "Certificate CN (common name) must match the username of the account"
+  csr_country_must_match_registrar_country: "Certificate C (country) must match the country of the registrar"
diff --git a/config/locales/et.yml b/config/locales/et.yml
index 51192c708..00cc7e11f 100644
--- a/config/locales/et.yml
+++ b/config/locales/et.yml
@@ -2,6 +2,10 @@ et:
   username: 'Kasutajanimi'
   password: 'Parool'
 
+  # Adding translation keys for certificate CSR validation
+  csr_common_name_must_match_username: "Sertifikaadi CN (üldine nimi) peab vastama konto kasutajanimele"
+  csr_country_must_match_registrar_country: "Sertifikaadi C (riik) peab vastama registripidaja riigile"
+
   time:
     formats:
       default: "%Y-%m-%d %H:%M"
diff --git a/test/integration/repp/v1/certificates/create_test.rb b/test/integration/repp/v1/certificates/create_test.rb
index 7ead82706..97813391b 100644
--- a/test/integration/repp/v1/certificates/create_test.rb
+++ b/test/integration/repp/v1/certificates/create_test.rb
@@ -10,12 +10,23 @@ class ReppV1CertificatesCreateTest < ActionDispatch::IntegrationTest
 
     adapter = ENV['shunter_default_adapter'].constantize.new
     adapter&.clear!
+    
+    @user.registrar.update!(address_country_code: 'ET',vat_rate: 22)
   end
 
   def test_creates_new_api_user_certificate_and_informs_admins
+    original_username = @user.username
+    @user.update!(username: 'host.ee') && @user.reload
+
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    headers = { 'Authorization' => "Basic #{token}" }
+
     assert_difference('Certificate.count') do
       assert_difference 'ActionMailer::Base.deliveries.size', +1 do
-        post repp_v1_certificates_path, headers: @auth_headers, params: request_body
+        post repp_v1_certificates_path, headers: headers, params: request_body
+
+        puts "Response status: #{response.status}"
+        puts "Response body: #{response.body}"
       end
     end
     json = JSON.parse(response.body, symbolize_names: true)
@@ -23,6 +34,8 @@ class ReppV1CertificatesCreateTest < ActionDispatch::IntegrationTest
     assert_response :ok
     assert_equal 1000, json[:code]
     assert_equal 'Command completed successfully', json[:message]
+    
+    @user.update!(username: original_username)
   end
 
   def test_return_error_when_invalid_certificate
diff --git a/test/models/certificate_test.rb b/test/models/certificate_test.rb
index 08a0dac3d..b6ba7a1bc 100644
--- a/test/models/certificate_test.rb
+++ b/test/models/certificate_test.rb
@@ -41,4 +41,56 @@ class CertificateTest < ActiveSupport::TestCase
     @certificate.update!(interface: Certificate::REGISTRAR, crt: nil)
     assert_not @certificate.revokable?
   end
+
+  def test_csr_common_name_must_match_username
+    api_user = @certificate.api_user
+    
+    new_cert = Certificate.new(
+      api_user: api_user,
+      csr: @certificate.csr
+    )
+    api_user.update!(username: 'different_username')
+    
+    new_cert.send(:validate_csr_parameters)
+    
+    assert_includes new_cert.errors.full_messages, I18n.t(:csr_common_name_must_match_username)
+  end
+  
+  def test_csr_country_validation
+    api_user = @certificate.api_user
+    csr_content = @certificate.csr
+    
+    new_cert = Certificate.new(
+      api_user: api_user,
+      csr: csr_content
+    )
+    api_user.registrar.update!(address_country_code: 'EE', vat_rate: 22)
+    
+    new_cert.send(:validate_csr_parameters)
+    
+    assert_not_includes new_cert.errors.full_messages, I18n.t(:csr_country_must_match_registrar_country)
+    
+    new_cert.errors.clear
+    api_user.registrar.update!(address_country_code: 'US', vat_rate: nil)
+    new_cert.send(:validate_csr_parameters)
+    
+    assert_includes new_cert.errors.full_messages, I18n.t(:csr_country_must_match_registrar_country)
+  end
+
+  def test_validation_in_controller_context
+    api_user = @certificate.api_user
+    api_user.update!(username: 'different_username')
+    
+    cert = Certificate.new(
+      api_user: api_user,
+      csr: @certificate.csr
+    )
+    
+    Rails.env.stub :test?, false do
+      assert_not cert.save
+      assert_includes cert.errors.full_messages, I18n.t(:csr_common_name_must_match_username)
+    end
+    
+    assert cert.save(validate: false)
+  end
 end