diff --git a/lib/philomena/topics.ex b/lib/philomena/topics.ex
index 741343db..fbbb05e2 100644
--- a/lib/philomena/topics.ex
+++ b/lib/philomena/topics.ex
@@ -40,6 +40,7 @@ defmodule Philomena.Topics do
 
   """
   def create_topic(forum, attribution, attrs \\ %{}) do
+    now = DateTime.utc_now() |> DateTime.truncate(:second)
     topic =
       %Topic{}
       |> Topic.creation_changeset(attrs, forum, attribution)
@@ -50,7 +51,7 @@ defmodule Philomena.Topics do
       {count, nil} =
         Topic
         |> where(id: ^topic.id)
-        |> repo.update_all(set: [last_post_id: hd(topic.posts).id])
+        |> repo.update_all(set: [last_post_id: hd(topic.posts).id, last_replied_to_at: now])
 
       {:ok, count}
     end)
diff --git a/lib/philomena/topics/topic.ex b/lib/philomena/topics/topic.ex
index 90f64332..d6ce7634 100644
--- a/lib/philomena/topics/topic.ex
+++ b/lib/philomena/topics/topic.ex
@@ -24,7 +24,7 @@ defmodule Philomena.Topics.Topic do
     field :post_count, :integer, default: 1
     field :view_count, :integer, default: 0
     field :sticky, :boolean, default: false
-    field :last_replied_to_at, :naive_datetime
+    field :last_replied_to_at, :utc_datetime
     field :locked_at, :utc_datetime
     field :deletion_reason, :string
     field :lock_reason, :string