diff --git a/include/sta/Liberty.hh b/include/sta/Liberty.hh
index 9ba8f7dd..d1ede379 100644
--- a/include/sta/Liberty.hh
+++ b/include/sta/Liberty.hh
@@ -137,6 +137,7 @@ public:
   LibertyCellSeq findLibertyCellsMatching(PatternMatch *pattern);
   // Liberty cells that are buffers.
   LibertyCellSeq *buffers();
+  LibertyCellSeq *inverters();
 
   DelayModelType delayModelType() const { return delay_model_type_; }
   void setDelayModelType(DelayModelType type);
@@ -369,6 +370,7 @@ protected:
   OcvDerateMap ocv_derate_map_;
   SupplyVoltageMap supply_voltage_map_;
   LibertyCellSeq *buffers_;
+  LibertyCellSeq *inverters_;
   DriverWaveformMap driver_waveform_map_;
   // Unnamed driver waveform.
   DriverWaveform *driver_waveform_default_;
diff --git a/liberty/Liberty.cc b/liberty/Liberty.cc
index d834210b..4ed08ec1 100644
--- a/liberty/Liberty.cc
+++ b/liberty/Liberty.cc
@@ -83,6 +83,7 @@ LibertyLibrary::LibertyLibrary(const char *name,
   ocv_arc_depth_(0.0),
   default_ocv_derate_(nullptr),
   buffers_(nullptr),
+  inverters_(nullptr),
   driver_waveform_default_(nullptr)
 {
   // Scalar templates are builtin.
@@ -125,6 +126,7 @@ LibertyLibrary::~LibertyLibrary()
     stringDelete(supply_name);
   }
   delete buffers_;
+  delete inverters_;
   driver_waveform_map_.deleteContents();
   delete driver_waveform_default_;
 }
@@ -148,6 +150,22 @@ LibertyLibrary::findLibertyCellsMatching(PatternMatch *pattern)
   return matches;
 }
 
+LibertyCellSeq *
+LibertyLibrary::inverters()
+{
+  if (inverters_ == nullptr) {
+    inverters_ = new LibertyCellSeq;
+    LibertyCellIterator cell_iter(this);
+    while (cell_iter.hasNext()) {
+      LibertyCell *cell = cell_iter.next();
+      if (!cell->dontUse()
+          && cell->isInverter())
+        inverters_->push_back(cell);
+    }
+  }
+  return inverters_;
+}
+
 LibertyCellSeq *
 LibertyLibrary::buffers()
 {