diff --git a/changelog b/changelog
index 7f47f308..0d405103 100644
--- a/changelog
+++ b/changelog
@@ -1,3 +1,6 @@
+Unreleased
+- Fixed a bug in the offset calculation of `.enqueue_at`.
+
 Version 3.0.0rc
 - Improved signal handling
 
diff --git a/lib/queue_classic/queue.rb b/lib/queue_classic/queue.rb
index c1004609..581e91fb 100644
--- a/lib/queue_classic/queue.rb
+++ b/lib/queue_classic/queue.rb
@@ -47,7 +47,7 @@ def enqueue(method, *args)
     # and args argument must be in the form described in the documentation for
     # the #enqueue method.
     def enqueue_at(timestamp, method, *args)
-      offset = Time.at(timestamp) - Time.now
+      offset = Time.at(timestamp).to_i - Time.now.to_i
       enqueue_in(offset, method, *args)
     end
 
diff --git a/test/queue_test.rb b/test/queue_test.rb
index 3b80c497..c711381c 100644
--- a/test/queue_test.rb
+++ b/test/queue_test.rb
@@ -28,12 +28,14 @@ def test_lock_when_empty
   end
 
   def test_lock_with_future_job_with_enqueue_in
+    now = Time.now
     QC.enqueue_in(2, "Klass.method")
     assert_nil QC.lock
     sleep 2
     job = QC.lock
     assert_equal("Klass.method", job[:method])
     assert_equal([], job[:args])
+    assert_equal((now + 2).to_i, job[:scheduled_at].to_i)
   end
 
   def test_lock_with_future_job_with_enqueue_at_with_a_time_object
@@ -44,6 +46,7 @@ def test_lock_with_future_job_with_enqueue_at_with_a_time_object
     job = QC.lock
     assert_equal("Klass.method", job[:method])
     assert_equal([], job[:args])
+    assert_equal(future.to_i, job[:scheduled_at].to_i)
   end
 
   def test_lock_with_future_job_with_enqueue_at_with_a_float_timestamp