diff --git a/app/controllers/todos_controller.rb b/app/controllers/todos_controller.rb
index 83207f76..69c6c621 100644
--- a/app/controllers/todos_controller.rb
+++ b/app/controllers/todos_controller.rb
@@ -8,7 +8,7 @@ class TodosController < ApplicationController
     :completed_archive, :check_deferred, :toggle_check, :toggle_star,
     :edit, :update, :create, :calendar, :auto_complete_for_tag]
   append_before_filter :get_todo_from_params, :only => [ :edit, :toggle_check, :toggle_star, :show, :update, :destroy ]
-  protect_from_forgery :except => [:auto_complete_for_tag]
+  protect_from_forgery :except => [:auto_complete_for_tag, :auto_complete_for_predecessor]
 
   session :off, :only => :index, :if => Proc.new { |req| is_feed_request(req) }
 
@@ -214,7 +214,25 @@ class TodosController < ApplicationController
     @original_item_project_id = @todo.project_id
     @original_item_was_deferred = @todo.deferred?
     @original_item_due = @todo.due
-    @original_item_due_id = get_due_id_for_calendar(@todo.due) 
+    @original_item_due_id = get_due_id_for_calendar(@todo.due)
+    @original_item_predecessor_list = @todo.predecessors.collect{|t| t.description}.join(', ')
+    if params[:predecessor_list]
+      logger.debug "---old #{@original_item_predecessor_list}"
+      logger.debug "---new #{params[:predecessor_list]}"
+      @todo.add_predecessor_list(params[:predecessor_list])
+      if @original_item_predecessor_list != params[:predecessor_list]
+        # Recalculate dependencies for this todo
+        if @todo.uncompleted_predecessors.empty?
+          if @todo.state == 'pending'
+            @todo.activate! # Activate pending if no uncompleted predecessors
+          end
+        else
+          if @todo.state == 'active'
+            @todo.block! # Block active if we got uncompleted predecessors
+          end
+        end
+      end
+    end
     
     if params['todo']['project_id'].blank? && !params['project_name'].nil?
       if params['project_name'] == 'None'
@@ -540,6 +558,28 @@ class TodosController < ApplicationController
     render :inline => "<%= auto_complete_result(@items, :name) %>"
   end
   
+  def auto_complete_for_predecessor
+    get_todo_from_params
+    # Begin matching todos in current project
+    @items = current_user.todos.find(:all, 
+      :conditions => [ 'NOT (id = ?) AND description LIKE ? AND project_id = ?', 
+                        @todo.id, 
+                        '%' + params[:predecessor_list] + '%',
+                        @todo.project_id ],
+      :order => 'description ASC',
+      :limit => 10
+    )
+    if @items.empty? # Match todos in other projects
+      @items = current_user.todos.find(:all, 
+        :conditions => [ 'NOT (id = ?) AND description LIKE ?', 
+                          params[:id], '%' + params[:predecessor_list] + '%' ],
+        :order => 'description ASC',
+        :limit => 10
+      )
+    end
+    render :inline => "<%= auto_complete_result(@items, :description) %>"
+  end
+  
   private
   
   def get_todo_from_params
diff --git a/app/helpers/todos_helper.rb b/app/helpers/todos_helper.rb
index ec7a2d3c..70c54385 100644
--- a/app/helpers/todos_helper.rb
+++ b/app/helpers/todos_helper.rb
@@ -116,6 +116,20 @@ module TodosHelper
     if tag_list.empty? then "" else "<span class=\"tags\">#{tag_list}</span>" end
   end
   
+  # TODO: Use DELIMITER
+  def predecessor_list_text
+    @todo.predecessors.collect{|t| t.description}.join(', ')
+  end
+  
+  def predecessor_list
+    predecessor_list = @todo.predecessors.collect{|t| 
+      '<span class="predecessor #{t.description}">' + 
+      link_to(t.name, :controller => "todos", :action => "tag", :id => t.name) + 
+      "</span>"
+    }.join('')
+    '<span class="predecessors">#{predecessor_list}</span>'
+  end
+  
   def deferred_due_date
     if @todo.deferred? && @todo.due
       "(action due on #{format_date(@todo.due)})"
diff --git a/app/models/todo.rb b/app/models/todo.rb
index 9c5488eb..06ab02d5 100644
--- a/app/models/todo.rb
+++ b/app/models/todo.rb
@@ -154,6 +154,39 @@ class Todo < ActiveRecord::Base
     return self.recurring_todo_id != nil
   end
   
+  def add_predecessor(predecessor)
+    logger.debug "add_predecessor #{predecessor.description}"
+  end
+  
+  # TODO: DELIMITER
+  # TODO: Todo::Error
+  # TODO: Handle todos with the same description
+  def add_predecessor_list(predecessor_list)
+    logger.debug "add_predecessor_list #{predecessor_list}"
+    raise "Can't handle other types than string for now" unless predecessor_list.kind_of? String
+    list = predecessor_list.split(',').map do |description| 
+      description.strip.squeeze(" ")            
+    end
+    current = self.predecessors.map(&:description)
+    remove_list = current - list
+    # This is probably a bit naive code...
+    remove_list.each do |description|
+      t = Todo.find_by_description(description)
+      logger.debug "Removing #{t.description} from #{self.description} as predecessor"
+      self.predecessors.delete(t)
+    end
+    add_list = list - current
+    # ... as is this?
+    add_list.each do |description|
+      t = Todo.find_by_description(description)
+      #raise Todo::Error, "predecessor could not be found: #{description}" if t.nil?
+      # Create dependency record
+      self.predecessors << t unless self.predecessors.include?(t)
+    end
+#    debugger
+    
+  end
+  
   # Rich Todo API
   
   def self.from_rich_message(user, default_context_id, description, notes)
diff --git a/app/views/todos/_edit_form.rhtml b/app/views/todos/_edit_form.rhtml
index e471984e..2f8e4bc5 100644
--- a/app/views/todos/_edit_form.rhtml
+++ b/app/views/todos/_edit_form.rhtml
@@ -46,13 +46,21 @@
   </a>
 </div>
 
+<label class="predecessor_list_label" for="<%= dom_id(@todo, 'predecessor_list') %>">Depends on (separate with commas)</label>
+<%= text_field_tag 'predecessor_list', predecessor_list_text, :id => dom_id(@todo, 'predecessor_list'), :size => 30, :tabindex => 15 %> 
+<%= content_tag("div", "", :id => dom_id(@todo, 'predecessor_list')+"_auto_complete", :class => "auto_complete") %>
+<%= auto_complete_field dom_id(@todo, 'predecessor_list'), {
+  :url => {:controller => 'todos', :action => 'auto_complete_for_predecessor', :id => @todo.id},
+  :tokens => [',']
+} %>
+
 <% if controller.controller_name == "project" || @todo.deferred? -%>
   <input type="hidden" name="on_project_page" value="true" />
 <% end -%>
 
 <div class="submit_box">
   <div class="widgets">
-    <button type="submit" class="positive" id="<%= dom_id(@todo, 'submit') %>" tabindex="15">
+    <button type="submit" class="positive" id="<%= dom_id(@todo, 'submit') %>" tabindex="16">
       <%=image_tag("accept.png", :alt => "") %>
       Update
     </button>