diff --git a/src/db/db/dbNetlistDeviceExtractor.cc b/src/db/db/dbNetlistDeviceExtractor.cc
index aa5b9f84a..7bc0d4caf 100644
--- a/src/db/db/dbNetlistDeviceExtractor.cc
+++ b/src/db/db/dbNetlistDeviceExtractor.cc
@@ -481,6 +481,10 @@ void NetlistDeviceExtractor::extract_devices (const std::vector<db::Region> & /*
 
 void NetlistDeviceExtractor::register_device_class (DeviceClass *device_class)
 {
+  std::auto_ptr<DeviceClass> holder (device_class);
+  tl_assert (device_class != 0);
+  tl_assert (m_netlist.get () != 0);
+
   if (mp_device_class != 0) {
     throw tl::Exception (tl::to_string (tr ("Device class already set")));
   }
@@ -488,12 +492,22 @@ void NetlistDeviceExtractor::register_device_class (DeviceClass *device_class)
     throw tl::Exception (tl::to_string (tr ("No device extractor/device class name set")));
   }
 
-  tl_assert (device_class != 0);
-  mp_device_class = device_class;
-  mp_device_class->set_name (m_name);
+  DeviceClass *existing = m_netlist->device_class_by_name (m_name);
+  if (existing) {
 
-  tl_assert (m_netlist.get () != 0);
-  m_netlist->add_device_class (device_class);
+    if (typeid (*existing) != typeid (*device_class)) {
+      throw tl::Exception (tl::to_string (tr ("Different device class already registered with the same name")));
+    }
+    mp_device_class = existing;
+
+  } else {
+
+    mp_device_class = holder.get ();
+    mp_device_class->set_name (m_name);
+
+    m_netlist->add_device_class (holder.release ());
+
+  }
 }
 
 const db::NetlistDeviceExtractorLayerDefinition &NetlistDeviceExtractor::define_layer (const std::string &name, const std::string &description)
diff --git a/src/db/unit_tests/dbNetlistExtractorTests.cc b/src/db/unit_tests/dbNetlistExtractorTests.cc
index e04637320..1dbdd0b25 100644
--- a/src/db/unit_tests/dbNetlistExtractorTests.cc
+++ b/src/db/unit_tests/dbNetlistExtractorTests.cc
@@ -2303,3 +2303,110 @@ TEST(10_DeviceExtractionWithBreakoutCells)
 
   db::compare_layouts (_this, ly, au);
 }
+
+TEST(11_DeviceExtractionWithSameClass)
+{
+  db::Layout ly;
+  db::LayerMap lmap;
+
+  unsigned int rmarker    = define_layer (ly, lmap, 1);
+  unsigned int poly       = define_layer (ly, lmap, 2);
+  unsigned int diff       = define_layer (ly, lmap, 3);
+  unsigned int contact    = define_layer (ly, lmap, 4);
+  unsigned int metal      = define_layer (ly, lmap, 5);
+
+  {
+    db::LoadLayoutOptions options;
+    options.get_options<db::CommonReaderOptions> ().layer_map = lmap;
+    options.get_options<db::CommonReaderOptions> ().create_other_layers = false;
+
+    std::string fn (tl::testsrc ());
+    fn = tl::combine_path (fn, "testdata");
+    fn = tl::combine_path (fn, "algo");
+    fn = tl::combine_path (fn, "device_extract_l11.gds");
+
+    tl::InputStream stream (fn);
+    db::Reader reader (stream);
+    reader.read (ly, options);
+  }
+
+  db::Cell &tc = ly.cell (*ly.begin_top_down ());
+
+  db::DeepShapeStore dss;
+  dss.set_text_enlargement (1);
+  dss.set_text_property_name (tl::Variant ("LABEL"));
+
+  //  original layers
+  db::Region rrmarker (db::RecursiveShapeIterator (ly, tc, rmarker), dss);
+  db::Region rpoly (db::RecursiveShapeIterator (ly, tc, poly), dss);
+  db::Region rdiff (db::RecursiveShapeIterator (ly, tc, diff), dss);
+  db::Region rcontact (db::RecursiveShapeIterator (ly, tc, contact), dss);
+  db::Region rmetal (db::RecursiveShapeIterator (ly, tc, metal), dss);
+
+  //  derived regions
+
+  db::Region rpoly_cap = rpoly - rrmarker;
+  db::Region rpoly_res = rpoly & rrmarker;
+  db::Region rdiff_cap = rdiff - rrmarker;
+  db::Region rdiff_res = rdiff & rrmarker;
+
+  //  perform the extraction
+
+  db::Netlist nl;
+  db::hier_clusters<db::PolygonRef> cl;
+
+  db::NetlistDeviceExtractorResistor polyres_ex ("RES", 50.0);
+  db::NetlistDeviceExtractorResistor diffres_ex ("RES", 150.0);
+
+  db::NetlistDeviceExtractor::input_layers dl;
+  dl["R"] = &rpoly_res;
+  dl["C"] = &rpoly_cap;
+  polyres_ex.extract (dss, 0, dl, nl, cl);
+
+  dl.clear ();
+  dl["R"] = &rdiff_res;
+  dl["C"] = &rdiff_cap;
+  diffres_ex.extract (dss, 0, dl, nl, cl);
+
+  //  perform the net extraction
+
+  db::NetlistExtractor net_ex;
+
+  db::Connectivity conn;
+  //  Intra-layer
+  conn.connect (rpoly_cap);
+  conn.connect (rdiff_cap);
+  conn.connect (rcontact);
+  //  Inter-layer
+  conn.connect (rpoly_cap,  rcontact);
+  conn.connect (rdiff_cap,  rcontact);
+  conn.connect (rmetal,     rcontact);
+
+  //  extract the nets
+
+  net_ex.extract_nets (dss, 0, conn, nl, cl);
+
+  std::string nl_au_string =
+    "circuit TOP ();\n"
+    "  device RES $1 (A=$1,B=$2) (R=175,L=2.8,W=0.8,A=0.56,P=3.6);\n"
+    "  device RES $2 (A=$2,B=$3) (R=175,L=2.8,W=0.8,A=0.56,P=3.6);\n"
+    "  device RES $3 (A=$3,B=$4) (R=525,L=2.8,W=0.8,A=0.56,P=3.6);\n"
+    "end;\n"
+  ;
+
+  //  compare netlist as string
+  CHECKPOINT ();
+  db::compare_netlist (_this, nl, nl_au_string);
+
+  nl.combine_devices ();
+
+  std::string nl_au_string_post =
+    "circuit TOP ();\n"
+    "  device RES $3 (A=$1,B=$4) (R=875,L=8.4,W=0.8,A=1.68,P=10.8);\n"
+    "end;\n"
+  ;
+
+  //  compare netlist as string
+  CHECKPOINT ();
+  db::compare_netlist (_this, nl, nl_au_string_post);
+}
diff --git a/testdata/algo/device_extract_l11.gds b/testdata/algo/device_extract_l11.gds
new file mode 100644
index 000000000..23e65f7d8
Binary files /dev/null and b/testdata/algo/device_extract_l11.gds differ