diff --git a/bookmarks/services/bookmarks.py b/bookmarks/services/bookmarks.py
index 0453dfc..441620b 100644
--- a/bookmarks/services/bookmarks.py
+++ b/bookmarks/services/bookmarks.py
@@ -7,6 +7,14 @@ from bookmarks.services.website_loader import load_website_metadata
 
 
 def create_bookmark(form: BookmarkForm, current_user: User):
+    # If URL is already bookmarked, then update it
+    existing_bookmark = Bookmark.objects.filter(owner=current_user, url=form.data['url']).first()
+
+    if existing_bookmark is not None:
+        update_form = BookmarkForm(data=form.data, instance=existing_bookmark)
+        update_bookmark(update_form, current_user)
+        return
+
     bookmark = form.save(commit=False)
     # Update website info
     _update_website_metadata(bookmark)
diff --git a/bookmarks/styles/bookmarks.scss b/bookmarks/styles/bookmarks.scss
index 06f789e..b245727 100644
--- a/bookmarks/styles/bookmarks.scss
+++ b/bookmarks/styles/bookmarks.scss
@@ -55,4 +55,15 @@ ul.bookmark-list {
   .form-icon.loading {
     visibility: hidden;
   }
+
+  .form-input-hint.bookmark-exists {
+    visibility: hidden;
+    color: $warning-color;
+
+    a {
+      color: $warning-color;
+      text-decoration: underline;
+      font-weight: bold;
+    }
+  }
 }
diff --git a/bookmarks/templates/bookmarks/edit.html b/bookmarks/templates/bookmarks/edit.html
index d5e6f54..6ebad75 100644
--- a/bookmarks/templates/bookmarks/edit.html
+++ b/bookmarks/templates/bookmarks/edit.html
@@ -8,7 +8,7 @@
                 <h2>Edit bookmark</h2>
             </div>
             <form action="{% url 'bookmarks:edit' bookmark_id %}" method="post" class="col-6 col-md-12" novalidate>
-                {% bookmark_form form all_tags %}
+                {% bookmark_form form all_tags bookmark_id %}
             </form>
         </section>
     </div>
diff --git a/bookmarks/templates/bookmarks/form.html b/bookmarks/templates/bookmarks/form.html
index 377c4c6..aaa7bbc 100644
--- a/bookmarks/templates/bookmarks/form.html
+++ b/bookmarks/templates/bookmarks/form.html
@@ -12,6 +12,9 @@
                 {{ form.url.errors }}
             </div>
         {% endif %}
+        <div class="form-input-hint bookmark-exists">
+            This URL is already bookmarked. You can <a href="#">edit</a> it or you can overwrite the existing bookmark by saving this form.
+        </div>
     </div>
     <div class="form-group">
         <label for="{{ form.tag_string.id_for_label }}" class="form-label">Tags</label>
@@ -77,28 +80,42 @@
     </script>
     <script type="application/javascript">
         /**
-         * Pre-fill title and description placeholders with metadata from website as soon as URL changes
+         * - Pre-fill title and description placeholders with metadata from website as soon as URL changes
+         * - Show hint if URL is already bookmarked
          */
         (function init() {
             const urlInput = document.getElementById('{{ form.url.id_for_label }}');
             const titleInput = document.getElementById('{{ form.title.id_for_label }}');
             const descriptionInput = document.getElementById('{{ form.description.id_for_label }}');
+            const editedBookmarkId = {{ bookmark_id }}
 
-            urlInput.addEventListener('input', updateMetadata);
+            urlInput.addEventListener('input', checkUrl);
 
-            function updateMetadata() {
+            function checkUrl() {
                 toggleIcon(titleInput, true);
                 toggleIcon(descriptionInput, true);
 
-                const websiteUrl = urlInput.value;
-                const requestUrl = `{% url 'bookmarks:api.website_metadata' %}?url=${websiteUrl}`;
+                const websiteUrl = encodeURIComponent(urlInput.value);
+                const requestUrl = `{% url 'bookmarks:api.check_url' %}?url=${websiteUrl}`;
                 fetch(requestUrl)
                     .then(response => response.json())
-                    .then(metadata => {
+                    .then(data => {
+                        const metadata = data.metadata
                         titleInput.setAttribute('placeholder', metadata.title || '');
                         descriptionInput.setAttribute('placeholder', metadata.description || '');
                         toggleIcon(titleInput, false);
                         toggleIcon(descriptionInput, false);
+
+                        // Display hint if URL is already bookmarked
+                        const bookmarkExistsHint = document.querySelector('.form-input-hint.bookmark-exists')
+                        const editExistingBookmarkLink = bookmarkExistsHint.querySelector('a')
+
+                        if(data.bookmark && data.bookmark.id !== editedBookmarkId) {
+                            bookmarkExistsHint.style['visibility'] = 'visible'
+                            editExistingBookmarkLink.href = data.bookmark.edit_url
+                        } else {
+                            bookmarkExistsHint.style['visibility'] = 'hidden'
+                        }
                     });
             }
 
@@ -107,7 +124,7 @@
                 icon.style['visibility'] = show ? 'visible' : 'hidden';
             }
 
-            if (urlInput.value) updateMetadata();
+            if (urlInput.value) checkUrl();
         })();
     </script>
 </div>
diff --git a/bookmarks/templates/bookmarks/new.html b/bookmarks/templates/bookmarks/new.html
index 0ee2f6a..9399fff 100644
--- a/bookmarks/templates/bookmarks/new.html
+++ b/bookmarks/templates/bookmarks/new.html
@@ -8,7 +8,7 @@
                 <h2>New bookmark</h2>
             </div>
             <form action="{% url 'bookmarks:new' %}" method="post" class="col-6 col-md-12" novalidate>
-                {% bookmark_form form all_tags auto_close %}
+                {% bookmark_form form all_tags auto_close=auto_close %}
             </form>
         </section>
     </div>
diff --git a/bookmarks/templatetags/bookmarks.py b/bookmarks/templatetags/bookmarks.py
index dfaaefb..98ea43b 100644
--- a/bookmarks/templatetags/bookmarks.py
+++ b/bookmarks/templatetags/bookmarks.py
@@ -9,7 +9,7 @@ register = template.Library()
 
 
 @register.inclusion_tag('bookmarks/form.html', name='bookmark_form')
-def bookmark_form(form: BookmarkForm, all_tags: List[Tag], auto_close: bool = False):
+def bookmark_form(form: BookmarkForm, all_tags: List[Tag], bookmark_id: int = 0, auto_close: bool = False):
 
     all_tag_names = [tag.name for tag in all_tags]
     all_tags_string = build_tag_string(all_tag_names, ' ')
@@ -17,7 +17,8 @@ def bookmark_form(form: BookmarkForm, all_tags: List[Tag], auto_close: bool = Fa
     return {
         'form': form,
         'auto_close': auto_close,
-        'all_tags': all_tags_string
+        'all_tags': all_tags_string,
+        'bookmark_id': bookmark_id
     }
 
 
diff --git a/bookmarks/urls.py b/bookmarks/urls.py
index 90b8487..ef265a3 100644
--- a/bookmarks/urls.py
+++ b/bookmarks/urls.py
@@ -20,5 +20,5 @@ urlpatterns = [
     path('settings/import', views.settings.bookmark_import, name='settings.import'),
     path('settings/export', views.settings.bookmark_export, name='settings.export'),
     # API
-    path('api/website_metadata', views.api.website_metadata, name='api.website_metadata'),
+    path('api/check_url', views.api.check_url, name='api.check_url'),
 ]
diff --git a/bookmarks/views/api.py b/bookmarks/views/api.py
index b4dd8fe..f8a0620 100644
--- a/bookmarks/views/api.py
+++ b/bookmarks/views/api.py
@@ -1,11 +1,27 @@
 from django.contrib.auth.decorators import login_required
+from django.forms import model_to_dict
 from django.http import JsonResponse
+from django.urls import reverse
 
 from bookmarks.services.website_loader import load_website_metadata
+from bookmarks.models import Bookmark
 
 
 @login_required
-def website_metadata(request):
+def check_url(request):
     url = request.GET.get('url')
+    bookmark = Bookmark.objects.filter(owner=request.user, url=url).first()
+    existing_bookmark_data = None
+
+    if bookmark is not None:
+        existing_bookmark_data = {
+            'id': bookmark.id,
+            'edit_url': reverse('bookmarks:edit', args=[bookmark.id])
+        }
+
     metadata = load_website_metadata(url)
-    return JsonResponse(metadata.to_dict())
+
+    return JsonResponse({
+        'bookmark': existing_bookmark_data,
+        'metadata': metadata.to_dict()
+    })