diff --git a/lib/towerops/device_profiles.ex b/lib/towerops/device_profiles.ex
index 54b9b5ea..83249a2d 100644
--- a/lib/towerops/device_profiles.ex
+++ b/lib/towerops/device_profiles.ex
@@ -82,6 +82,30 @@ defmodule Towerops.DeviceProfiles do
     |> Repo.insert()
   end
 
+  @doc """
+  Upserts a device profile by OS name.
+
+  If a profile with the given OS exists, it updates it and deletes all associated
+  definitions (detection rules, sensors, etc.) to allow re-import from scratch.
+  Otherwise, creates a new profile.
+  """
+  def upsert_profile(attrs \\ %{}) do
+    os = attrs[:os] || attrs["os"]
+
+    case get_profile(os) do
+      nil ->
+        # Create new profile
+        create_profile(attrs)
+
+      existing_profile ->
+        # Delete all associated definitions to get a clean slate
+        delete_profile_associations(existing_profile.id)
+
+        # Update the profile
+        update_profile(existing_profile, attrs)
+    end
+  end
+
   @doc """
   Updates a device profile.
   """
@@ -154,6 +178,22 @@ defmodule Towerops.DeviceProfiles do
 
   # Private functions
 
+  defp delete_profile_associations(profile_id) do
+    # Delete in order to respect foreign key constraints
+    Repo.delete_all(
+      from s in SensorState,
+        join: sd in SensorDefinition,
+        on: s.sensor_definition_id == sd.id,
+        where: sd.device_profile_id == ^profile_id
+    )
+
+    Repo.delete_all(from s in SensorDefinition, where: s.device_profile_id == ^profile_id)
+    Repo.delete_all(from p in ProcessorDefinition, where: p.device_profile_id == ^profile_id)
+    Repo.delete_all(from m in MemPoolDefinition, where: m.device_profile_id == ^profile_id)
+    Repo.delete_all(from o in OSDefinition, where: o.device_profile_id == ^profile_id)
+    Repo.delete_all(from d in DetectionRule, where: d.device_profile_id == ^profile_id)
+  end
+
   defp list_profiles_with_detection_rules do
     Repo.all(
       from p in DeviceProfile,
diff --git a/lib/towerops/device_profiles/importer.ex b/lib/towerops/device_profiles/importer.ex
index d16f5cef..2a6ad96f 100644
--- a/lib/towerops/device_profiles/importer.ex
+++ b/lib/towerops/device_profiles/importer.ex
@@ -118,9 +118,11 @@ defmodule Towerops.DeviceProfiles.Importer do
       priority: data["priority"] || 100
     }
 
-    case DeviceProfiles.create_profile(attrs) do
+    # Upsert profile - updates if exists, creates if new
+    # Deletes all associated definitions before update for clean re-import
+    case DeviceProfiles.upsert_profile(attrs) do
       {:ok, profile} ->
-        # Create detection rules
+        # Create detection rules (associations were deleted in upsert)
         :ok = create_detection_rules(profile.id, data["discovery"] || [])
         {:ok, profile}