diff --git a/physionet-django/events/models.py b/physionet-django/events/models.py
index 1b904b950e..dcc09cda27 100644
--- a/physionet-django/events/models.py
+++ b/physionet-django/events/models.py
@@ -59,6 +59,12 @@ def get_cohosts(self):
         """
         return self.participants.filter(is_cohost=True)
 
+    def has_ended(self):
+        """
+        Returns true if the event has ended.
+        """
+        return self.end_date < timezone.now().date()
+
 
 class EventParticipant(models.Model):
     """
diff --git a/physionet-django/events/templates/events/event_entries.html b/physionet-django/events/templates/events/event_entries.html
index c2f8c5370c..ed998096bc 100644
--- a/physionet-django/events/templates/events/event_entries.html
+++ b/physionet-django/events/templates/events/event_entries.html
@@ -17,21 +17,23 @@
             <td>{{ participant.user.email }}</td>
             <td>{{ participant.user.is_credentialed }}</td>
             <td>
-                {% if participant.is_cohost %}
-                    <form class="manage-cohost" action="{% url 'manage_co_hosts' %}">
-                        {% csrf_token %}
-                        <input type="text" name="event" value="{{ event.slug }}" hidden>
-                        <input type="text" name="participant" value="{{ participant.id }}" hidden>
-                        <input type="submit" value="Remove cohost" class="btn btn-sm btn-danger">
-                    </form>
-                {% else %}
-                     <form class="manage-cohost" action="{% url 'manage_co_hosts' %}">
-                        {% csrf_token %}
-                        <input type="text" name="event" value="{{ event.slug }}" hidden>
-                        <input type="text" name="participant" value="{{ participant.id }}" hidden>
-                        <input type="submit" value="Make cohost" class="btn btn-sm btn-success">
-                    </form>
-                {% endif %}
+            {% if not event.has_ended %}
+              {% if participant.is_cohost %}
+                <form class="manage-cohost" action="{% url 'manage_co_hosts' %}">
+                    {% csrf_token %}
+                    <input type="text" name="event" value="{{ event.slug }}" hidden>
+                    <input type="text" name="participant" value="{{ participant.id }}" hidden>
+                    <input type="submit" value="Remove cohost" class="btn btn-sm btn-danger">
+                </form>
+              {% else %}
+                  <form class="manage-cohost" action="{% url 'manage_co_hosts' %}">
+                    {% csrf_token %}
+                    <input type="text" name="event" value="{{ event.slug }}" hidden>
+                    <input type="text" name="participant" value="{{ participant.id }}" hidden>
+                    <input type="submit" value="Make cohost" class="btn btn-sm btn-success">
+                </form>
+              {% endif %}
+            {% endif %}
             </td>
           </tr>
         {% endfor %}