diff --git a/dlls/mshtml/omnavigator.c b/dlls/mshtml/omnavigator.c
index 7479180f80e..6e912d35e29 100644
--- a/dlls/mshtml/omnavigator.c
+++ b/dlls/mshtml/omnavigator.c
@@ -226,8 +226,16 @@ static HRESULT WINAPI OmNavigator_get_opsProfile(IOmNavigator *iface, IHTMLOpsPr
 static HRESULT WINAPI OmNavigator_toString(IOmNavigator *iface, BSTR *String)
 {
     OmNavigator *This = OMNAVIGATOR_THIS(iface);
-    FIXME("(%p)->(%p)\n", This, String);
-    return E_NOTIMPL;
+
+    static const WCHAR objectW[] = {'[','o','b','j','e','c','t',']',0};
+
+    TRACE("(%p)->(%p)\n", This, String);
+
+    if(!String)
+        return E_INVALIDARG;
+
+    *String = SysAllocString(objectW);
+    return *String ? S_OK : E_OUTOFMEMORY;
 }
 
 static HRESULT WINAPI OmNavigator_get_cpuClass(IOmNavigator *iface, BSTR *p)
diff --git a/dlls/mshtml/tests/dom.c b/dlls/mshtml/tests/dom.c
index e10e41a278b..e9dfef75e3f 100644
--- a/dlls/mshtml/tests/dom.c
+++ b/dlls/mshtml/tests/dom.c
@@ -2492,6 +2492,15 @@ static void test_navigator(IHTMLDocument2 *doc)
     ok(!memcmp(bstr, v40, sizeof(v40)), "appVersion is %s\n", wine_dbgstr_w(bstr));
     SysFreeString(bstr);
 
+    hres = IOmNavigator_toString(navigator, NULL);
+    ok(hres == E_INVALIDARG, "toString failed: %08x\n", hres);
+
+    bstr = NULL;
+    hres = IOmNavigator_toString(navigator, &bstr);
+    ok(hres == S_OK, "toString failed: %08x\n", hres);
+    ok(!strcmp_wa(bstr, "[object]"), "toString returned %s\n", wine_dbgstr_w(bstr));
+    SysFreeString(bstr);
+
     ref = IOmNavigator_Release(navigator);
     ok(!ref, "navigator should be destroyed here\n");
 }