diff --git a/app/models/user.rb b/app/models/user.rb
index 4ee8ead2..0439f237 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -108,6 +108,7 @@ class User < ActiveRecord::Base
 
   before_create :crypt_password, :generate_token
   before_update :crypt_password
+  before_destroy :destroy_dependencies, :delete_taggings, prepend: true  # run before deleting todos, projects, contexts, etc.
 
   def validate_auth_type
     unless Tracks::Config.auth_schemes.include?(auth_type)
@@ -220,4 +221,16 @@ protected
     auth_type == 'database' && crypted_password.blank? || password.present?
   end
 
+  def destroy_dependencies
+    ids = todos.pluck(:id)
+    pred_deps = Dependency.where(predecessor_id: ids).destroy_all
+    succ_deps = Dependency.where(predecessor_id: ids).destroy_all
+  end
+
+  def delete_taggings
+    ids = todos.pluck(:id)
+    taggings = Tagging.where(taggable_id: ids).pluck(:id)
+    Tagging.where(id: taggings).delete_all
+  end
+
 end
diff --git a/test/models/user_test.rb b/test/models/user_test.rb
index b2e45ff8..a7122c0c 100644
--- a/test/models/user_test.rb
+++ b/test/models/user_test.rb
@@ -393,12 +393,14 @@ class UserTest < ActiveSupport::TestCase
     nr_of_contexts = u.contexts.count
     nr_of_rec_todos = u.recurring_todos.count
     nr_of_notes = u.notes.count
+    nr_of_deps = (Dependency.where(predecessor_id: u.todos.pluck(:id)).pluck(:id) + Dependency.where(successor_id: u.todos.pluck(:id)).pluck(:id)).uniq.count
 
     expect_todos_count = Todo.count - nr_of_todos
     expect_projects_count = Project.count - nr_of_projects
     expect_contexts_count = Context.count - nr_of_contexts
     expect_rec_todos_count = RecurringTodo.count - nr_of_rec_todos
     expect_notes_count = Note.count - nr_of_notes
+    expect_deps_count = Dependency.count - nr_of_deps
 
     u.destroy
 
@@ -407,7 +409,7 @@ class UserTest < ActiveSupport::TestCase
     assert_equal expect_contexts_count, Context.count, "expected #{nr_of_contexts} contexts to be gone"
     assert_equal expect_rec_todos_count, RecurringTodo.count, "expected #{nr_of_rec_todos} repeating todos to be gone"
     assert_equal expect_notes_count, Note.count, "expected #{nr_of_notes} notes to be gone"
-
+    assert_equal expect_deps_count, Dependency.count, "expected #{nr_of_deps} dependencies to be gone"
   end
     
   protected