diff --git a/src/applications/maniphest/conduit/ManiphestQueryConduitAPIMethod.php b/src/applications/maniphest/conduit/ManiphestQueryConduitAPIMethod.php
--- a/src/applications/maniphest/conduit/ManiphestQueryConduitAPIMethod.php
+++ b/src/applications/maniphest/conduit/ManiphestQueryConduitAPIMethod.php
@@ -102,7 +102,10 @@
 
     $full_text = $request->getValue('fullText');
     if ($full_text) {
-      $query->withFullTextSearch($full_text);
+      throw new Exception(
+        pht(
+          'Parameter "fullText" is no longer supported. Use method '.
+          '"maniphest.search" with the "query" constraint instead.'));
     }
 
     $status = $request->getValue('status');
diff --git a/src/applications/maniphest/query/ManiphestTaskQuery.php b/src/applications/maniphest/query/ManiphestTaskQuery.php
--- a/src/applications/maniphest/query/ManiphestTaskQuery.php
+++ b/src/applications/maniphest/query/ManiphestTaskQuery.php
@@ -24,8 +24,6 @@
   private $subtaskIDs;
   private $subtypes;
 
-  private $fullTextSearch   = '';
-
   private $status           = 'status-any';
   const STATUS_ANY          = 'status-any';
   const STATUS_OPEN         = 'status-open';
@@ -115,11 +113,6 @@
     return $this;
   }
 
-  public function withFullTextSearch($fulltext_search) {
-    $this->fullTextSearch = $fulltext_search;
-    return $this;
-  }
-
   public function setGroupBy($group) {
     $this->groupBy = $group;
 
@@ -329,7 +322,6 @@
 
     $where[] = $this->buildStatusWhereClause($conn);
     $where[] = $this->buildOwnerWhereClause($conn);
-    $where[] = $this->buildFullTextWhereClause($conn);
 
     if ($this->taskIDs !== null) {
       $where[] = qsprintf(
@@ -481,36 +473,6 @@
     return '('.implode(') OR (', $subclause).')';
   }
 
-  private function buildFullTextWhereClause(AphrontDatabaseConnection $conn) {
-    if (!strlen($this->fullTextSearch)) {
-      return null;
-    }
-
-    // In doing a fulltext search, we first find all the PHIDs that match the
-    // fulltext search, and then use that to limit the rest of the search
-    $fulltext_query = id(new PhabricatorSavedQuery())
-      ->setEngineClassName('PhabricatorSearchApplicationSearchEngine')
-      ->setParameter('query', $this->fullTextSearch);
-
-    // NOTE: Setting this to something larger than 10,000 will raise errors in
-    // Elasticsearch, and billions of results won't fit in memory anyway.
-    $fulltext_query->setParameter('limit', 10000);
-    $fulltext_query->setParameter('types',
-      array(ManiphestTaskPHIDType::TYPECONST));
-
-    $fulltext_results = PhabricatorSearchService::executeSearch(
-      $fulltext_query);
-
-    if (empty($fulltext_results)) {
-      $fulltext_results = array(null);
-    }
-
-    return qsprintf(
-      $conn,
-      'task.phid IN (%Ls)',
-      $fulltext_results);
-  }
-
   protected function buildJoinClauseParts(AphrontDatabaseConnection $conn) {
     $open_statuses = ManiphestTaskStatus::getOpenStatusConstants();
     $edge_table = PhabricatorEdgeConfig::TABLE_NAME_EDGE;
diff --git a/src/applications/maniphest/query/ManiphestTaskSearchEngine.php b/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
--- a/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
+++ b/src/applications/maniphest/query/ManiphestTaskSearchEngine.php
@@ -86,9 +86,6 @@
           pht('Search for tasks with given subtypes.'))
         ->setDatasource(new ManiphestTaskSubtypeDatasource())
         ->setIsHidden($hide_subtypes),
-      id(new PhabricatorSearchTextField())
-        ->setLabel(pht('Contains Words'))
-        ->setKey('fulltext'),
       id(new PhabricatorSearchThreeStateField())
         ->setLabel(pht('Open Parents'))
         ->setKey('hasParents')
@@ -144,7 +141,6 @@
       'statuses',
       'priorities',
       'subtypes',
-      'fulltext',
       'hasParents',
       'hasSubtasks',
       'parentIDs',
@@ -220,10 +216,6 @@
       $query->withOpenSubtasks($map['hasSubtasks']);
     }
 
-    if (strlen($map['fulltext'])) {
-      $query->withFullTextSearch($map['fulltext']);
-    }
-
     if ($map['parentIDs']) {
       $query->withParentTaskIDs($map['parentIDs']);
     }