diff --git a/smart_card_connector_app/src/_locales/en/messages.json b/smart_card_connector_app/src/_locales/en/messages.json
index 13ccb0aa7..dd71ae558 100644
--- a/smart_card_connector_app/src/_locales/en/messages.json
+++ b/smart_card_connector_app/src/_locales/en/messages.json
@@ -19,6 +19,10 @@
     "message": "Smart Card Connector",
     "description": "The header displayed in the main window"
   },
+  "nonChromeOsWarning": {
+    "message": "Warning: The app is intended to be run on Chrome OS only!",
+    "description": "The text that is displayed as a warning when the app is executed on non-Chrome OS systems"
+  },
   "windowClose": {
     "message": "Close",
     "description": "Accessibility text for close button"
diff --git a/smart_card_connector_app/src/window-main.js b/smart_card_connector_app/src/window-main.js
index 993ef0dda..e70fcd1d9 100644
--- a/smart_card_connector_app/src/window-main.js
+++ b/smart_card_connector_app/src/window-main.js
@@ -28,6 +28,7 @@ goog.require('GoogleSmartCard.I18n');
 goog.require('GoogleSmartCard.Logging');
 goog.require('GoogleSmartCard.PopupWindow.Client');
 goog.require('goog.dom');
+goog.require('goog.dom.classlist');
 goog.require('goog.events');
 goog.require('goog.events.EventType');
 goog.require('goog.log.Logger');
@@ -45,10 +46,6 @@ var logger = GSC.Logging.getScopedLogger('ConnectorApp.MainWindow');
 
 logger.info('The main window is created');
 
-function closeWindowClickListener() {
-  chrome.app.window.current().close();
-}
-
 goog.events.listen(
     goog.dom.getElement('close-window'),
     goog.events.EventType.CLICK,
@@ -59,8 +56,27 @@ GSC.ConnectorApp.Window.AppsDisplaying.initialize();
 GSC.ConnectorApp.Window.DevicesDisplaying.initialize();
 GSC.ConnectorApp.Window.LogsExporting.initialize();
 
+GSC.I18n.adjustElementsTranslation();
+
 GSC.PopupWindow.Client.showWindow();
 
-GSC.I18n.adjustElementsTranslation();
+displayNonChromeOsWarningIfNeeded();
+
+function closeWindowClickListener() {
+  chrome.app.window.current().close();
+}
+
+function displayNonChromeOsWarningIfNeeded() {
+  chrome.runtime.getPlatformInfo(function(platformInfo) {
+    /** @type {string} */
+    var os = platformInfo['os'];
+    if (os != 'cros') {
+      logger.info('Displaying the warning regarding non-Chrome OS system ' +
+                  '(the current OS is "' + os + '")');
+      goog.dom.classlist.remove(
+          goog.dom.getElement('non-chrome-os-warning'), 'hidden');
+    }
+  });
+}
 
 });  // goog.scope
diff --git a/smart_card_connector_app/src/window.css b/smart_card_connector_app/src/window.css
index 54cfb4e3e..2d5881037 100644
--- a/smart_card_connector_app/src/window.css
+++ b/smart_card_connector_app/src/window.css
@@ -17,6 +17,10 @@
   -webkit-user-select: text;
 }
 
+.hidden {
+  display: none;
+}
+
 html,
 body,
 button {
@@ -58,6 +62,13 @@ body {
   -webkit-user-select: none;
 }
 
+#non-chrome-os-warning {
+  color: red;
+  font-size: 15px;
+  font-weight: 600;
+  margin-top: 15px;
+}
+
 .list-header {
   color: #4285f4;
   font-size: 12px;
diff --git a/smart_card_connector_app/src/window.html b/smart_card_connector_app/src/window.html
index 70910f016..d75f6c1d9 100644
--- a/smart_card_connector_app/src/window.html
+++ b/smart_card_connector_app/src/window.html
@@ -25,6 +25,8 @@
     <h1 id="header" data-i18n="mainWindowHeader"></h1>
   </div>
 
+  <div id="non-chrome-os-warning" class="hidden" data-i18n="nonChromeOsWarning"></div>
+
   <button id="close-window" data-i18n-aria-label="windowClose">×</button>
 
   <h2 id="readers-list-header" class="list-header" data-i18n="readersListHeader"></h2>