diff --git a/tarteaucitron.js b/tarteaucitron.js
index 0f1bb75..85b2f66 100644
--- a/tarteaucitron.js
+++ b/tarteaucitron.js
@@ -380,7 +380,7 @@ var tarteaucitron = {
                 for (i = 0; i < cat.length; i += 1) {
                     html += '         <li id="tarteaucitronServicesTitle_' + cat[i] + '" class="tarteaucitronHidden">';
                     html += '            <div class="tarteaucitronTitle" role="heading" aria-level="2">';
-                    html += '               <button type="button" class="catToggleBtn" data-cat="tarteaucitronDetails' + cat[i] + '"><span class="tarteaucitronPlus" aria-hidden="true"></span> ' + tarteaucitron.lang[cat[i]].title + '</button>';
+                    html += '               <button type="button" class="catToggleBtn" aria-expanded="false" data-cat="tarteaucitronDetails' + cat[i] + '"><span class="tarteaucitronPlus" aria-hidden="true"></span> ' + tarteaucitron.lang[cat[i]].title + '</button>';
                     html += '            </div>';
                     html += '            <div id="tarteaucitronDetails' + cat[i] + '" class="tarteaucitronDetails tarteaucitronInfoBox">';
                     html += '               ' + tarteaucitron.lang[cat[i]].details;
@@ -749,6 +749,11 @@ var tarteaucitron = {
                         toggleBtns[i].dataset.index = i;
                         tarteaucitron.addClickEventToElement(toggleBtns[i], function () {
                             tarteaucitron.userInterface.toggle('tarteaucitronDetails' + cat[this.dataset.index], 'tarteaucitronInfoBox');
+                            if (document.getElementById('tarteaucitronDetails' + cat[this.dataset.index]).style.display === 'block') {
+                                this.setAttribute('aria-expanded', 'true');
+                            } else {
+                                this.setAttribute('aria-expanded', 'false');
+                            }
                             return false;
                         });
                     }