diff --git a/app/controllers/votes_controller.rb b/app/controllers/votes_controller.rb
index efc032a..ef34536 100644
--- a/app/controllers/votes_controller.rb
+++ b/app/controllers/votes_controller.rb
@@ -28,19 +28,25 @@ class VotesController < ApplicationController
 
     require 'csv'
 
-    CSV.parse(votes_csv, :headers => %i[voter_email short_name voter_login_id voter_password]) do |row|
+    headers = %i[
+      voter_email
+      short_name
+      voter_login_id
+      voter_password
+    ]
+    votes = CSV.parse(votes_csv, headers: headers).map { |row|
       csv_fields = row.to_hash
       email = csv_fields[:voter_email]
       user = User.find_by(room_id: room_id, email: email)
-      vote_fields = {
+      {
         :room_id => room_id,
         :user_id => user.id,
         :election_slug => csv_fields[:short_name],
         :voter_login_id => csv_fields[:voter_login_id],
         :voter_password => csv_fields[:voter_password],
       }
-      Vote.create!(vote_fields)
-    end
+    }
+    Vote.upsert_all(votes, unique_by: [:user_id, :election_slug])
 
     respond_to do |format|
       format.html { redirect_to room_users_url(room_id), notice: 'Votes were successfully created.' }