diff --git a/PhysicsAnalysis/D3PDMaker/TruthD3PDAnalysis/src/SimpleTruthParticleFilterTool.cxx b/PhysicsAnalysis/D3PDMaker/TruthD3PDAnalysis/src/SimpleTruthParticleFilterTool.cxx
index 7ff4a1f18ba5e8b0171e76fbee66a0809654d5d7..997025e37b1f82d302b313f39a92c5a7ddcf52b1 100644
--- a/PhysicsAnalysis/D3PDMaker/TruthD3PDAnalysis/src/SimpleTruthParticleFilterTool.cxx
+++ b/PhysicsAnalysis/D3PDMaker/TruthD3PDAnalysis/src/SimpleTruthParticleFilterTool.cxx
@@ -46,12 +46,20 @@ SimpleTruthParticleFilterTool::isAccepted (const HepMC::GenParticle* p)
   bool last = std::abs(p->pdg_id())==15;
   if ( abs(p->pdg_id())==15 && p->status()!=1 && p->end_vertex() ){
     // Special handling for taus - take the ones that are last in the tau chain
+#ifdef HEPMC3
+    for (auto pit: p->end_vertex()->particles_out()){
+      if (!pit || std::abs(pit->pdg_id())!=15) continue;
+      last=false;
+      break;
+    }
+#else
     for (HepMC::GenVertex::particles_out_const_iterator pit=p->end_vertex()->particles_out_const_begin(); pit!=p->end_vertex()->particles_out_const_end();++pit){
       if (!(*pit) ||
           abs((*pit)->pdg_id())!=15) continue;
       last=false;
       break;
     }
+#endif    
     if (!last) return false;
   }
 
diff --git a/Tracking/TrkValidation/TrkVertexFitterValidationTools/src/TrueTracksNtupleTool.cxx b/Tracking/TrkValidation/TrkVertexFitterValidationTools/src/TrueTracksNtupleTool.cxx
index d42f765b5ed9433de3e5ab1262c55d5f60199d18..11814b238395f428619a8d7e8808867e51557b17 100755
--- a/Tracking/TrkValidation/TrkVertexFitterValidationTools/src/TrueTracksNtupleTool.cxx
+++ b/Tracking/TrkValidation/TrkVertexFitterValidationTools/src/TrueTracksNtupleTool.cxx
@@ -134,15 +134,18 @@ StatusCode Trk::TrueTracksNtupleTool::fillTrueTracksInfo(const TrackCollection&
             if (msgLvl(MSG::DEBUG)) msg (MSG::DEBUG) << " truth is missing" << endmsg;
          } else {  
              TrackTruth trk_truth=found->second;
-             const HepMC::GenParticle * particle;
-             particle = trk_truth.particleLink();
-             HepMC:: GenVertex* prod_vtx = particle->production_vertex();
+             auto particle = trk_truth.particleLink();
+             auto prod_vtx = particle->production_vertex();
              //fill prod vertex
              m_prod_x->push_back(prod_vtx->position().x());
              m_prod_y->push_back(prod_vtx->position().y());
              m_prod_z->push_back(prod_vtx->position().z());
 
+#ifdef HEPMC3
+             auto   parent_iter = prod_vtx->particles_in().begin();
+#else
              HepMC::GenVertex::particle_iterator   parent_iter = prod_vtx->particles_begin(HepMC::parents);
+#endif
              m_parent_id->push_back((*parent_iter)->pdg_id());
              m_particle_id->push_back(particle->pdg_id());
             }
diff --git a/Trigger/TrigT1/TrigT1NSWSimTools/src/MMLoadVariables.cxx b/Trigger/TrigT1/TrigT1NSWSimTools/src/MMLoadVariables.cxx
index e07e4c49f8b0272a728351dcd852fc4f61f97489..fc429f89b5a0b20c4b4afd97e763e84173b5da94 100644
--- a/Trigger/TrigT1/TrigT1NSWSimTools/src/MMLoadVariables.cxx
+++ b/Trigger/TrigT1/TrigT1NSWSimTools/src/MMLoadVariables.cxx
@@ -71,18 +71,22 @@ MMLoadVariables::MMLoadVariables(StoreGateSvc* evtStore, const MuonGM::MuonDetec
 
       for(const auto it : *truthContainer) {  //first loop in MMT_loader::load_event
         const HepMC::GenEvent *subEvent = it;
+#ifdef HEPMC3
+        for(auto particle : subEvent->particles()) {
+#else
         HepMC::ConstGenEventParticleRange particle_range = subEvent->particle_range();
         for(const auto pit : particle_range) {
           const HepMC::GenParticle *particle = pit;
-          const HepMC::FourVector& momentum = particle->momentum();
+#endif
+          const HepMC::FourVector momentum = particle->momentum();
           int k=trackRecordCollection->size(); //number of mu entries
-          if(particle->barcode() == 10001 && std::abs(particle->pdg_id())==13){
+          if(HepMC::barcode(particle) == 10001 && std::abs(particle->pdg_id())==13){
             thePart.SetPtEtaPhiE(momentum.perp(),momentum.eta(),momentum.phi(),momentum.e());
             for(const auto & mit : *trackRecordCollection ) {
               if(k>0&&j<k){
                 const CLHEP::Hep3Vector mumomentum = mit.GetMomentum();
                 const CLHEP::Hep3Vector muposition = mit.GetPosition();
-                pdg=particle->barcode();
+                pdg=HepMC::barcode(particle);
                 phiEntry = mumomentum.getPhi();
                 etaEntry = mumomentum.getEta();
                 phiPosition = muposition.getPhi();
@@ -90,10 +94,14 @@ MMLoadVariables::MMLoadVariables(StoreGateSvc* evtStore, const MuonGM::MuonDetec
               }
             }//muentry loop
               int l=0;
+#ifdef HEPMC3
+              for(auto vertex1 : subEvent->vertices()) {
+#else
               HepMC::ConstGenEventVertexRange vertex_range = subEvent->vertex_range();
               for(const auto vit : vertex_range) {
                 if(l!=0){break;}//get first vertex of iteration, may want to change this
                 const HepMC::GenVertex *vertex1 = vit;
+#endif
                 const HepMC::FourVector& position = vertex1->position();
                 vertex=TVector3(position.x(),position.y(),position.z());
                 l++;
@@ -160,11 +168,8 @@ MMLoadVariables::MMLoadVariables(StoreGateSvc* evtStore, const MuonGM::MuonDetec
             //match to truth particle
             TLorentzVector truthPart;
             for(auto it1 : *truthContainer) {  //Must be a more elegant way... should work for now though
-              const HepMC::GenEvent *subEvent1 = it1;
-              HepMC::ConstGenEventParticleRange particle_range1 = subEvent1->particle_range();
-              for(auto pit1 : particle_range1) {
-                const HepMC::GenParticle *particle1 = pit1;
-                const HepMC::FourVector& momentum1 = particle1->momentum();
+              for(auto particle1 : *it1) {
+                const HepMC::FourVector momentum1 = particle1->momentum();
                 truthPart.SetPtEtaPhiE(momentum1.perp(),momentum1.eta(),momentum1.phi(),momentum1.e());
               }//end particle loop
             }//end truth container loop (1 iteration) for matching