diff --git a/src/application/config/constants.php b/src/application/config/constants.php
index d9265a83..cd2f8507 100644
--- a/src/application/config/constants.php
+++ b/src/application/config/constants.php
@@ -81,5 +81,8 @@ define('ANY_PROVIDER', 'any-provider');
 define('CALENDAR_VIEW_DEFAULT', 'default'); 
 define('CALENDAR_VIEW_TABLE', 'table'); 
 
+define('AVAILABILITIES_TYPE_FLEXIBLE', 'flexible');
+define('AVAILABILITIES_TYPE_FIXED', 'fixed');
+
 /* End of file constants.php */
 /* Location: ./application/config/constants.php */
diff --git a/src/application/models/Services_model.php b/src/application/models/Services_model.php
index c3c840ab..9f582599 100644
--- a/src/application/models/Services_model.php
+++ b/src/application/models/Services_model.php
@@ -135,6 +135,13 @@ class Services_Model extends CI_Model {
             }
         }
 
+        // Availabilities type must have the correct value. 
+        if ($service['availabilities_type'] !== NULL && $service['availabilities_type'] !== AVAILABILITIES_TYPE_FLEXIBLE 
+                && $service['availabilities_type'] !== AVAILABILITIES_TYPE_FIXED) {
+            throw new Exception('Service availabilities type must be either ' . AVAILABILITIES_TYPE_FLEXIBLE 
+                        . ' or ' . AVAILABILITIES_TYPE_FIXED . ' (given ' .  $service['availabilities_type'] . ')');
+        }
+
         return TRUE;
     }
 
diff --git a/src/application/views/backend/services.php b/src/application/views/backend/services.php
index 2258700c..d408f538 100644
--- a/src/application/views/backend/services.php
+++ b/src/application/views/backend/services.php
@@ -119,6 +119,18 @@
                     <select id="service-category" class="form-control"></select>
                 </div>
 
+                <div class="form-group">
+                    <label for="service-availabilities-type"><?php echo $this->lang->line('availabilities_type'); ?></label>
+                    <select id="service-availabilities-type" class="form-control">
+                        <option value="<?php echo AVAILABILITIES_TYPE_FLEXIBLE; ?>">
+                            <?php echo $this->lang->line('flexible'); ?>
+                        </option>
+                        <option value="<?php echo AVAILABILITIES_TYPE_FIXED; ?>">
+                            <?php echo $this->lang->line('fixed'); ?>
+                        </option>
+                    </select>
+                </div>
+
                 <div class="form-group">
                     <label for="service-description"><?php echo $this->lang->line('description'); ?></label>
                     <textarea id="service-description" rows="4" class="form-control"></textarea>
diff --git a/src/assets/js/backend_services_helper.js b/src/assets/js/backend_services_helper.js
index 1c6d83f1..af0ea076 100644
--- a/src/assets/js/backend_services_helper.js
+++ b/src/assets/js/backend_services_helper.js
@@ -112,7 +112,8 @@
                 duration: $('#service-duration').val(),
                 price: $('#service-price').val(),
                 currency: $('#service-currency').val(),
-                description: $('#service-description').val()
+                description: $('#service-description').val(),
+                availabilities_type: $('#service-availabilities-type').val()
             };
 
             if ($('#service-category').val() !== 'null') {
@@ -277,6 +278,7 @@
         $('#service-price').val(service.price);
         $('#service-currency').val(service.currency);
         $('#service-description').val(service.description);
+        $('#service-availabilities-type').val(service.availabilities_type);
 
         var categoryId = (service.id_service_categories !== null) ? service.id_service_categories : 'null';
         $('#service-category').val(categoryId);