diff --git a/src/application/controllers/appointments.php b/src/application/controllers/appointments.php
index b779f334..548913b8 100755
--- a/src/application/controllers/appointments.php
+++ b/src/application/controllers/appointments.php
@@ -279,6 +279,12 @@ class Appointments extends CI_Controller {
         $this->load->model('settings_model');
 
         try {
+			// Do not continue if there was no provider selected.
+			if (empty($_POST['provider_id'])) {
+				echo json_encode(array());
+				return;
+			}
+
             // If manage mode is TRUE then the following we should not consider the selected
             // appointment when calculating the available time periods of the provider.
             $exclude_appointments = ($_POST['manage_mode'] === 'true')
diff --git a/src/assets/js/frontend_book.js b/src/assets/js/frontend_book.js
index 495bf63d..6d873512 100644
--- a/src/assets/js/frontend_book.js
+++ b/src/assets/js/frontend_book.js
@@ -158,6 +158,12 @@ var FrontendBook = {
          * be perfomed, depending the current wizard step.
          */
         $('.button-next').click(function() {
+            // If we are on the first step and there is not provider selected do not continue
+            // with the next step.
+            if ($(this).attr('data-step_index') === '1' && $('#select-provider').val() == null) {
+                return;
+            }
+
             // If we are on the 2nd tab then the user should have an appointment hour
             // selected.
             if ($(this).attr('data-step_index') === '2') {