diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2201,12 +2201,14 @@
     'PhabricatorAuthConfirmLinkController' => 'applications/auth/controller/PhabricatorAuthConfirmLinkController.php',
     'PhabricatorAuthContactNumber' => 'applications/auth/storage/PhabricatorAuthContactNumber.php',
     'PhabricatorAuthContactNumberController' => 'applications/auth/controller/contact/PhabricatorAuthContactNumberController.php',
+    'PhabricatorAuthContactNumberDisableController' => 'applications/auth/controller/contact/PhabricatorAuthContactNumberDisableController.php',
     'PhabricatorAuthContactNumberEditController' => 'applications/auth/controller/contact/PhabricatorAuthContactNumberEditController.php',
     'PhabricatorAuthContactNumberEditEngine' => 'applications/auth/editor/PhabricatorAuthContactNumberEditEngine.php',
     'PhabricatorAuthContactNumberEditor' => 'applications/auth/editor/PhabricatorAuthContactNumberEditor.php',
     'PhabricatorAuthContactNumberNumberTransaction' => 'applications/auth/xaction/PhabricatorAuthContactNumberNumberTransaction.php',
     'PhabricatorAuthContactNumberPHIDType' => 'applications/auth/phid/PhabricatorAuthContactNumberPHIDType.php',
     'PhabricatorAuthContactNumberQuery' => 'applications/auth/query/PhabricatorAuthContactNumberQuery.php',
+    'PhabricatorAuthContactNumberStatusTransaction' => 'applications/auth/xaction/PhabricatorAuthContactNumberStatusTransaction.php',
     'PhabricatorAuthContactNumberTransaction' => 'applications/auth/storage/PhabricatorAuthContactNumberTransaction.php',
     'PhabricatorAuthContactNumberTransactionQuery' => 'applications/auth/query/PhabricatorAuthContactNumberTransactionQuery.php',
     'PhabricatorAuthContactNumberTransactionType' => 'applications/auth/xaction/PhabricatorAuthContactNumberTransactionType.php',
@@ -7904,12 +7906,14 @@
       'PhabricatorDestructibleInterface',
     ),
     'PhabricatorAuthContactNumberController' => 'PhabricatorAuthController',
+    'PhabricatorAuthContactNumberDisableController' => 'PhabricatorAuthContactNumberController',
     'PhabricatorAuthContactNumberEditController' => 'PhabricatorAuthContactNumberController',
     'PhabricatorAuthContactNumberEditEngine' => 'PhabricatorEditEngine',
     'PhabricatorAuthContactNumberEditor' => 'PhabricatorApplicationTransactionEditor',
     'PhabricatorAuthContactNumberNumberTransaction' => 'PhabricatorAuthContactNumberTransactionType',
     'PhabricatorAuthContactNumberPHIDType' => 'PhabricatorPHIDType',
     'PhabricatorAuthContactNumberQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
+    'PhabricatorAuthContactNumberStatusTransaction' => 'PhabricatorAuthContactNumberTransactionType',
     'PhabricatorAuthContactNumberTransaction' => 'PhabricatorModularTransaction',
     'PhabricatorAuthContactNumberTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
     'PhabricatorAuthContactNumberTransactionType' => 'PhabricatorModularTransactionType',
diff --git a/src/applications/auth/application/PhabricatorAuthApplication.php b/src/applications/auth/application/PhabricatorAuthApplication.php
--- a/src/applications/auth/application/PhabricatorAuthApplication.php
+++ b/src/applications/auth/application/PhabricatorAuthApplication.php
@@ -111,6 +111,8 @@
             'PhabricatorAuthContactNumberEditController',
           '(?P<id>[1-9]\d*)/' =>
             'PhabricatorAuthContactNumberViewController',
+          '(?P<action>disable|enable)/(?P<id>[1-9]\d*)/' =>
+            'PhabricatorAuthContactNumberDisableController',
         ),
       ),
 
diff --git a/src/applications/auth/controller/contact/PhabricatorAuthContactNumberDisableController.php b/src/applications/auth/controller/contact/PhabricatorAuthContactNumberDisableController.php
new file mode 100644
--- /dev/null
+++ b/src/applications/auth/controller/contact/PhabricatorAuthContactNumberDisableController.php
@@ -0,0 +1,87 @@
+<?php
+
+final class PhabricatorAuthContactNumberDisableController
+  extends PhabricatorAuthContactNumberController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $request->getViewer();
+    $id = $request->getURIData('id');
+
+    $number = id(new PhabricatorAuthContactNumberQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($id))
+      ->requireCapabilities(
+        array(
+          PhabricatorPolicyCapability::CAN_VIEW,
+          PhabricatorPolicyCapability::CAN_EDIT,
+        ))
+      ->executeOne();
+    if (!$number) {
+      return new Aphront404Response();
+    }
+
+    $is_disable = ($request->getURIData('action') == 'disable');
+    $id = $number->getID();
+    $cancel_uri = $number->getURI();
+
+    if ($request->isFormPost()) {
+      $xactions = array();
+
+      if ($is_disable) {
+        $new_status = PhabricatorAuthContactNumber::STATUS_DISABLED;
+      } else {
+        $new_status = PhabricatorAuthContactNumber::STATUS_ACTIVE;
+      }
+
+      $xactions[] = id(new PhabricatorAuthContactNumberTransaction())
+        ->setTransactionType(
+          PhabricatorAuthContactNumberStatusTransaction::TRANSACTIONTYPE)
+        ->setNewValue($new_status);
+
+      $editor = id(new PhabricatorAuthContactNumberEditor())
+        ->setActor($viewer)
+        ->setContentSourceFromRequest($request)
+        ->setContinueOnNoEffect(true)
+        ->setContinueOnMissingFields(true);
+
+      try {
+        $editor->applyTransactions($number, $xactions);
+      } catch (PhabricatorApplicationTransactionValidationException $ex) {
+        // This happens when you enable a number which collides with another
+        // number.
+        return $this->newDialog()
+          ->setTitle(pht('Changing Status Failed'))
+          ->setValidationException($ex)
+          ->addCancelButton($cancel_uri);
+      }
+
+      return id(new AphrontRedirectResponse())->setURI($cancel_uri);
+    }
+
+    $number_display = phutil_tag(
+      'strong',
+      array(),
+      $number->getDisplayName());
+
+    if ($is_disable) {
+      $title = pht('Disable Contact Number');
+      $body = pht(
+        'Disable the contact number %s?',
+        $number_display);
+      $button = pht('Disable Number');
+    } else {
+      $title = pht('Enable Contact Number');
+      $body = pht(
+        'Enable the contact number %s?',
+        $number_display);
+      $button = pht('Enable Number');
+    }
+
+    return $this->newDialog()
+      ->setTitle($title)
+      ->appendParagraph($body)
+      ->addSubmitButton($button)
+      ->addCancelButton($cancel_uri);
+  }
+
+}
diff --git a/src/applications/auth/controller/contact/PhabricatorAuthContactNumberViewController.php b/src/applications/auth/controller/contact/PhabricatorAuthContactNumberViewController.php
--- a/src/applications/auth/controller/contact/PhabricatorAuthContactNumberViewController.php
+++ b/src/applications/auth/controller/contact/PhabricatorAuthContactNumberViewController.php
@@ -54,6 +54,10 @@
       ->setHeader($number->getObjectName())
       ->setPolicyObject($number);
 
+    if ($number->isDisabled()) {
+      $view->setStatus('fa-ban', 'red', pht('Disabled'));
+    }
+
     return $view;
   }
 
@@ -92,6 +96,24 @@
         ->setDisabled(!$can_edit)
         ->setWorkflow(!$can_edit));
 
+
+    if ($number->isDisabled()) {
+      $disable_uri = $this->getApplicationURI("contact/enable/{$id}/");
+      $disable_name = pht('Enable Contact Number');
+      $disable_icon = 'fa-check';
+    } else {
+      $disable_uri = $this->getApplicationURI("contact/disable/{$id}/");
+      $disable_name = pht('Disable Contact Number');
+      $disable_icon = 'fa-ban';
+    }
+
+    $curtain->addAction(
+      id(new PhabricatorActionView())
+        ->setName($disable_name)
+        ->setIcon($disable_icon)
+        ->setHref($disable_uri)
+        ->setWorkflow(true));
+
     return $curtain;
   }
 
diff --git a/src/applications/auth/storage/PhabricatorAuthContactNumber.php b/src/applications/auth/storage/PhabricatorAuthContactNumber.php
--- a/src/applications/auth/storage/PhabricatorAuthContactNumber.php
+++ b/src/applications/auth/storage/PhabricatorAuthContactNumber.php
@@ -93,10 +93,32 @@
   }
 
   public function save() {
-    $this->uniqueKey = $this->newUniqueKey();
+    // We require that active contact numbers be unique, but it's okay to
+    // disable a number and then reuse it somewhere else.
+    if ($this->isDisabled()) {
+      $this->uniqueKey = null;
+    } else {
+      $this->uniqueKey = $this->newUniqueKey();
+    }
+
     return parent::save();
   }
 
+  public static function getStatusNameMap() {
+    return ipull(self::getStatusPropertyMap(), 'name');
+  }
+
+  private static function getStatusPropertyMap() {
+    return array(
+      self::STATUS_ACTIVE => array(
+        'name' => pht('Active'),
+      ),
+      self::STATUS_DISABLED => array(
+        'name' => pht('Disabled'),
+      ),
+    );
+  }
+
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
diff --git a/src/applications/auth/xaction/PhabricatorAuthContactNumberStatusTransaction.php b/src/applications/auth/xaction/PhabricatorAuthContactNumberStatusTransaction.php
new file mode 100644
--- /dev/null
+++ b/src/applications/auth/xaction/PhabricatorAuthContactNumberStatusTransaction.php
@@ -0,0 +1,59 @@
+<?php
+
+final class PhabricatorAuthContactNumberStatusTransaction
+  extends PhabricatorAuthContactNumberTransactionType {
+
+  const TRANSACTIONTYPE = 'status';
+
+  public function generateOldValue($object) {
+    return $object->getStatus();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setStatus($value);
+  }
+
+  public function getTitle() {
+    $new = $this->getNewValue();
+
+    if ($new === PhabricatorAuthContactNumber::STATUS_DISABLED) {
+      return pht(
+        '%s disabled this contact number.',
+        $this->renderAuthor());
+    } else {
+      return pht(
+        '%s enabled this contact number.',
+        $this->renderAuthor());
+    }
+  }
+
+  public function validateTransactions($object, array $xactions) {
+    $errors = array();
+
+    $map = PhabricatorAuthContactNumber::getStatusNameMap();
+
+    foreach ($xactions as $xaction) {
+      $new_value = $xaction->getNewValue();
+
+      if (!isset($map[$new_value])) {
+        $errors[] = $this->newInvalidError(
+          pht(
+            'Status ("%s") is not a valid contact number status. Valid '.
+            'status constants are: %s.',
+            $new_value,
+            implode(', ', array_keys($map))),
+          $xaction);
+        continue;
+      }
+
+      // NOTE: Enabling a contact number may cause us to collide with another
+      // active contact number. However, there might also be a transaction in
+      // this group that changes the number itself. Since we can't easily
+      // predict if we'll collide or not, just let the duplicate key logic
+      // handle it when we do.
+    }
+
+    return $errors;
+  }
+
+}