diff --git a/views/login.erb b/views/login.erb
index fd64e04..ada5979 100644
--- a/views/login.erb
+++ b/views/login.erb
@@ -1,7 +1,9 @@
 <h1><%= _("Login") %></h1>
+
 <% if @error %>
   <p class="error"><%= @error %></p>
 <% end %>
+
 <form action="/login" method="POST">
   <p>
     <label for="email"><%= _("Email") %></label>
diff --git a/views/signup.erb b/views/signup.erb
index 3ee2e58..7eb7ff3 100644
--- a/views/signup.erb
+++ b/views/signup.erb
@@ -1,13 +1,32 @@
 <h1><%= _("Create account") %></h1>
 
+<% if @errors %>
+<% @errors.each do |error| %>
+  <% if error.attribute == :password and error.type == :blank %>
+  <p class="error"><%= _("Specify a password.") %></p>
+  <% end %>
+<% end %>
+<% end %>
+
+<% if @user and @user.errors.any? %>
+<% @user.errors.each do |error| %>
+  <% if error.attribute == :email and error.type == :invalid %>
+  <p class="error"><%= _("Email is not a valid email address.") %></p>
+  <% end %>
+  <% if error.attribute == :email and error.type == :taken %>
+  <p class="error"><%= _("An account already exists for %{email}.") % { email: @user.email } %></p>
+  <% end %>
+<% end %>
+<% end %>
+
 <form action="/signup" method="post">
   <p>
     <label for="email"><%= _("Email") %></label>
-    <input type="text" name="email">
+    <input type="text" name="email" value="<%= params[:email] %>">
   </p>
   <p>
     <label for="password"><%= _("Password") %></label>
-    <input type="password" name="password">
+    <input type="password" name="password" value="<%= params[:password] %>">
   </p>
   <button type="submit"><%= _("Create account") %></button>
 </form>
diff --git a/vote.rb b/vote.rb
index c70ec7f..71f7f01 100644
--- a/vote.rb
+++ b/vote.rb
@@ -28,6 +28,8 @@ class User < ActiveRecord::Base
   has_many :ratings
   has_many :organizers
   has_many :votes, through: :organizers
+  validates :email, uniqueness: true
+  validates :email, format: URI::MailTo::EMAIL_REGEXP
 end
 
 class Organizer < ActiveRecord::Base
@@ -81,9 +83,21 @@ get '/signup' do
 end
 
 post '/signup' do
-  @user = User.create(email: params[:email],
-                      password: hash_password(params[:password]))
-  redirect '/'
+  @user = User.create(email: params[:email])
+  @errors = []
+  if params[:password].empty?
+    @errors << OpenStruct.new(:attribute => :password, :type => :blank)
+  else
+    @user.password = hash_password(params[:password])
+  end
+  if @errors.empty? and @user.valid?
+    @user.save
+    session.clear
+    session[:user_id] = @user.id
+    redirect '/'
+  else
+    erb :signup
+  end
 end
 
 get '/login' do
@@ -97,7 +111,7 @@ post '/login' do
     session[:user_id] = user.id
     redirect '/'
   else
-    @error = 'Username or password was incorrect'
+    @error = _("Incorrect email or password.")
     erb :login
   end
 end