diff --git a/carma_cooperative_perception/src/msg_conversion.cpp b/carma_cooperative_perception/src/msg_conversion.cpp
index 9cc3a8d369..a6ca846902 100644
--- a/carma_cooperative_perception/src/msg_conversion.cpp
+++ b/carma_cooperative_perception/src/msg_conversion.cpp
@@ -244,7 +244,23 @@ auto to_detection_list_msg(
 
     detection.header.stamp = to_time_msg(detection_time);
 
-    detection.id = std::to_string(common_data.detected_id.object_id);
+    // TemporaryID and octet string terms come from the SAE J2735 message definitions
+    static constexpr auto to_string = [](const std::vector<std::uint8_t> & temporary_id) {
+      std::string str;
+      str.reserve(2 * std::size(temporary_id));  // Two hex characters per octet string
+
+      std::array<char, 2> buffer;
+      for (const auto & octet_string : temporary_id) {
+        std::to_chars(std::begin(buffer), std::end(buffer), octet_string, 16);
+        str.push_back(std::toupper(std::get<0>(buffer)));
+        str.push_back(std::toupper(std::get<1>(buffer)));
+      }
+
+      return str;
+    };
+
+    detection.id =
+      to_string(sdsm.source_id.id) + "-" + std::to_string(common_data.detected_id.object_id);
 
     const auto pos_offset{PositionOffsetXYZ::from_msg(common_data.pos)};
     detection.pose.pose.position = to_position_msg(MapCoordinate{
diff --git a/carma_cooperative_perception/test/test_msg_conversion.cpp b/carma_cooperative_perception/test/test_msg_conversion.cpp
index 720b8cf0ca..b2763b40e2 100644
--- a/carma_cooperative_perception/test/test_msg_conversion.cpp
+++ b/carma_cooperative_perception/test/test_msg_conversion.cpp
@@ -58,6 +58,7 @@ TEST(ToTimeMsg, NulloptSeconds)
 TEST(ToDetectionMsg, Simple)
 {
   carma_v2x_msgs::msg::SensorDataSharingMessage sdsm_msg;
+  sdsm_msg.source_id.id = {0xBA, 0xDD, 0xCA, 0xFE};
   sdsm_msg.sdsm_time_stamp.second.millisecond = 1000;
   sdsm_msg.sdsm_time_stamp.presence_vector |= sdsm_msg.sdsm_time_stamp.SECOND;
   sdsm_msg.ref_pos.longitude = -90.703125;  // degrees
@@ -66,7 +67,7 @@ TEST(ToDetectionMsg, Simple)
   sdsm_msg.ref_pos.elevation = 300.0;  // m
 
   carma_v2x_msgs::msg::DetectedObjectData object_data;
-  object_data.detected_object_common_data.detected_id.object_id = 0xBEEF;
+  object_data.detected_object_common_data.detected_id.object_id = 1;
   object_data.detected_object_common_data.measurement_time.measurement_time_offset = -0.1;  // s
 
   object_data.detected_object_common_data.heading.heading = 34;  // true heading; degrees
@@ -118,7 +119,7 @@ TEST(ToDetectionMsg, Simple)
   EXPECT_DOUBLE_EQ(detection.accel.accel.linear.y, 1.0);
   EXPECT_NEAR(detection.accel.accel.linear.z, 2.4 * 9.80665, 1e-4);
 
-  EXPECT_EQ(detection.id, std::to_string(0xBEEF));
+  EXPECT_EQ(detection.id, "BADDCAFE-1");
   EXPECT_EQ(detection.motion_model, detection.MOTION_MODEL_CTRV);
 }