diff --git a/examples/mdi/sequence_driver.py b/examples/mdi/sequence_driver.py
index b0b26f6d7f..33dcf61b70 100644
--- a/examples/mdi/sequence_driver.py
+++ b/examples/mdi/sequence_driver.py
@@ -155,7 +155,7 @@ def perform_tasks(world,mdicomm,dummy):
     # request virial tensor
 
     mdi.MDI_Send_command("<STRESS",mdicomm)
-    virial = mdi.MDI_Recv(6,mdi.MDI_DOUBLE,mdicomm)
+    virial = mdi.MDI_Recv(9,mdi.MDI_DOUBLE,mdicomm)
     virial = world.bcast(virial,root=0)
 
     # request forces
@@ -165,10 +165,10 @@ def perform_tasks(world,mdicomm,dummy):
     world.Bcast(forces,root=0)
 
     # final output from each calculation
-    # pressure = just virial component, no kinetic component
+    # pressure = trace of virial tensor, no kinetic component
   
     aveeng = pe/natoms
-    pressure = (virial[0] + virial[1] + virial[2]) / 3.0
+    pressure = (virial[0] + virial[4] + virial[8]) / 3.0
 
     m = 0
     fx = fy = fz = 0.0
diff --git a/src/MDI/fix_mdi_qm.cpp b/src/MDI/fix_mdi_qm.cpp
index 0b05263f01..e819087844 100644
--- a/src/MDI/fix_mdi_qm.cpp
+++ b/src/MDI/fix_mdi_qm.cpp
@@ -329,18 +329,22 @@ void FixMDIQM::post_force(int vflag)
     }
   }
 
-  // optionally request pressure tensor from MDI engine, convert to virial
+  // optionally request stress tensor from MDI engine, convert to virial
   // qm_virial = fix output for global QM virial
 
   if (virialflag) {
     ierr = MDI_Send_command("<STRESS", mdicomm);
     if (ierr) error->all(FLERR, "MDI: <STRESS command");
-    ierr = MDI_Recv(qm_virial, 6, MDI_DOUBLE, mdicomm);
+    ierr = MDI_Recv(qm_virial, 9, MDI_DOUBLE, mdicomm);
     if (ierr) error->all(FLERR, "MDI: <STRESS data");
-    MPI_Bcast(qm_virial, 6, MPI_DOUBLE, 0, world);
+    MPI_Bcast(qm_virial, 9, MPI_DOUBLE, 0, world);
 
-    for (int i = 0; i < 6; i++)
-      qm_virial[i] *= mdi2lmp_pressure;
+    qm_virial_symmetric[0] = qm_virial[0] * mdi2lmp_pressure;
+    qm_virial_symmetric[1] = qm_virial[4] * mdi2lmp_pressure;
+    qm_virial_symmetric[2] = qm_virial[8] * mdi2lmp_pressure;
+    qm_virial_symmetric[3] = 0.5*(qm_virial[1]+qm_virial[3]) * mdi2lmp_pressure;
+    qm_virial_symmetric[4] = 0.5*(qm_virial[2]+qm_virial[6]) * mdi2lmp_pressure;
+    qm_virial_symmetric[5] = 0.5*(qm_virial[5]+qm_virial[7]) * mdi2lmp_pressure;
   }
 
   // optionally set fix->virial
@@ -356,7 +360,7 @@ void FixMDIQM::post_force(int vflag)
     else if (domain->dimension == 3)
       volume = domain->xprd * domain->yprd * domain->zprd;
     for (int i = 0; i < 6; i++)
-      virial[i] = qm_virial[i]*volume/nprocs;
+      virial[i] = qm_virial_symmetric[i]*volume/nprocs;
   }
 }
 
@@ -382,7 +386,7 @@ double FixMDIQM::compute_scalar()
 
 double FixMDIQM::compute_vector(int n)
 {
-  return qm_virial[n];
+  return qm_virial_symmetric[n];
 }
 
 /* ----------------------------------------------------------------------
diff --git a/src/MDI/fix_mdi_qm.h b/src/MDI/fix_mdi_qm.h
index 2d6f4b0d23..1db6a0cce2 100644
--- a/src/MDI/fix_mdi_qm.h
+++ b/src/MDI/fix_mdi_qm.h
@@ -47,7 +47,7 @@ class FixMDIQM : public Fix {
 
   double qm_energy;
   int lmpunits;
-  double qm_virial[6],qm_virial_all[6];
+  double qm_virial[9],qm_virial_symmetric[6];
   double **fqm;
 
   MDI_Comm mdicomm;
diff --git a/src/MDI/mdi_engine.cpp b/src/MDI/mdi_engine.cpp
index c5fc7e0b50..6a58512cfa 100644
--- a/src/MDI/mdi_engine.cpp
+++ b/src/MDI/mdi_engine.cpp
@@ -1413,16 +1413,21 @@ void MDIEngine::send_pe()
 
 /* ----------------------------------------------------------------------
    <STRESS command
-   send 6-component stress tensor (no kinetic energy term)
+   send 9-component stress tensor (no kinetic energy term)
 ---------------------------------------------------------------------- */
 
 void MDIEngine::send_stress()
 {
-  double vtensor[6];
+  double vtensor_full[9];
   press->compute_vector();
-  for (int i = 0; i < 6; i++) vtensor[i] = press->vector[i] * lmp2mdi_pressure;
+  vtensor_full[0] = press->vector[0] * lmp2mdi_pressure;
+  vtensor_full[4] = press->vector[1] * lmp2mdi_pressure;
+  vtensor_full[8] = press->vector[2] * lmp2mdi_pressure;
+  vtensor_full[1] = vtensor_full[3] = press->vector[3] * lmp2mdi_pressure;
+  vtensor_full[2] = vtensor_full[6] = press->vector[4] * lmp2mdi_pressure;
+  vtensor_full[5] = vtensor_full[7] = press->vector[5] * lmp2mdi_pressure;
 
-  int ierr = MDI_Send(vtensor, 6, MDI_DOUBLE, mdicomm);
+  int ierr = MDI_Send(vtensor_full, 9, MDI_DOUBLE, mdicomm);
   if (ierr) error->all(FLERR, "MDI: <STRESS data");
 }