diff --git a/src/calibre/gui2/tts/config.py b/src/calibre/gui2/tts/config.py
index c1d6ea28b2..1822a65802 100644
--- a/src/calibre/gui2/tts/config.py
+++ b/src/calibre/gui2/tts/config.py
@@ -3,6 +3,7 @@
 
 from qt.core import (
     QCheckBox,
+    QFont,
     QFormLayout,
     QHBoxLayout,
     QIcon,
@@ -136,20 +137,30 @@ class Voices(QTreeWidget):
         self.setHeaderHidden(True)
         self.system_default_voice = Voice()
         self.currentItemChanged.connect(self.voice_changed)
+        self.normal_font = f = self.font()
+        self.highlight_font = f = QFont(f)
+        f.setBold(True), f.setItalic(True)
 
     def sizeHint(self) -> QSize:
         return QSize(400, 500)
 
+    def set_item_downloaded_state(self, ans: QTreeWidgetItem) -> None:
+        voice = ans.data(0, Qt.ItemDataRole.UserRole)
+        is_downloaded = bool(voice.engine_data and voice.engine_data.get('is_downloaded'))
+        ans.setFont(0, self.highlight_font if is_downloaded else self.normal_font)
+
     def set_voices(self, all_voices: tuple[Voice, ...], current_voice: str, engine_metadata: EngineMetadata) -> None:
         self.clear()
         current_item = None
         def qv(parent, voice):
             nonlocal current_item
-            ans = QTreeWidgetItem(parent, [voice.short_text(engine_metadata)])
+            text = voice.short_text(engine_metadata)
+            ans = QTreeWidgetItem(parent, [text])
             ans.setData(0, Qt.ItemDataRole.UserRole, voice)
             ans.setToolTip(0, voice.tooltip(engine_metadata))
             if current_voice == voice.name:
                 current_item = ans
+            self.set_item_downloaded_state(ans)
             return ans
         qv(self.invisibleRootItem(), self.system_default_voice)
         vmap = {}
@@ -182,6 +193,11 @@ class Voices(QTreeWidget):
         if ci is not None:
             return ci.data(0, Qt.ItemDataRole.UserRole)
 
+    def refresh_current_item(self) -> None:
+        ci = self.currentItem()
+        if ci is not None:
+            self.set_item_downloaded_state(ci)
+
 
 class EngineSpecificConfig(QWidget):
 
@@ -357,6 +373,7 @@ class ConfigDialog(Dialog):
         else:
             b.setIcon(QIcon.ic('download-metadata.png'))
             b.setText(_('Download voice'))
+        self.engine_specific_config.voices.refresh_current_item()
 
     def voice_action(self):
         self.engine_specific_config.voice_action()
diff --git a/src/calibre/gui2/tts/piper.py b/src/calibre/gui2/tts/piper.py
index 1b30308c6a..7386ef4e1a 100644
--- a/src/calibre/gui2/tts/piper.py
+++ b/src/calibre/gui2/tts/piper.py
@@ -406,6 +406,9 @@ class Piper(TTSBackend):
         ans = []
         lang_voices_map = {}
         self._voice_name_map = {}
+        downloaded = set()
+        with suppress(OSError):
+            downloaded = set(os.listdir(self.cache_dir))
         for bcp_code, voice_map in d['lang_map'].items():
             lang, sep, country = bcp_code.partition('_')
             lang = canonicalize_lang(lang) or lang
@@ -416,9 +419,10 @@ class Piper(TTSBackend):
                     q = Quality.from_piper_quality(qual)
                     if best_qual is None or q.value < best_qual.value:
                         best_qual = q
+                        mf = f'{bcp_code}-{voice_name}-{qual}.onnx'
                         voice = Voice(bcp_code + ':' + voice_name, lang, country, human_name=voice_name, quality=q, engine_data={
                             'model_url': e['model'], 'config_url': e['config'],
-                            'model_filename': f'{bcp_code}-{voice_name}-{qual}.onnx',
+                            'model_filename': mf, 'is_downloaded': mf in downloaded,
                         })
                 if voice:
                     ans.append(voice)
@@ -442,9 +446,13 @@ class Piper(TTSBackend):
         lang = canonicalize_lang(lang) or lang
         return self._voice_for_lang.get(lang) or self._voice_for_lang['eng']
 
+    @property
+    def cache_dir(self) -> str:
+        return os.path.join(cache_dir(), 'piper-voices')
+
     def _paths_for_voice(self, voice: Voice) -> tuple[str, str]:
         fname = voice.engine_data['model_filename']
-        model_path = os.path.join(cache_dir(), 'piper-voices', fname)
+        model_path = os.path.join(self.cache_dir, fname)
         config_path = os.path.join(os.path.dirname(model_path), fname + '.json')
         return model_path, config_path
 
@@ -462,6 +470,7 @@ class Piper(TTSBackend):
         for path in self._paths_for_voice(v):
             with suppress(FileNotFoundError):
                 os.remove(path)
+        v.engine_data['is_downloaded'] = False
 
     def _download_voice(self, voice: Voice, download_even_if_exists: bool = False) -> tuple[str, str]:
         model_path, config_path = self._paths_for_voice(voice)
@@ -475,6 +484,7 @@ class Piper(TTSBackend):
                 voice.engine_data['config_url']: (config_path, _('Neural network metadata')),
             }, parent=widget_parent(self), headless=getattr(QApplication.instance(), 'headless', False)
         )
+        voice.engine_data['is_downloaded'] = bool(ok)
         return (model_path, config_path) if ok else ('', '')
 
     def download_voice(self, v: Voice) -> None: