diff --git a/src/fix_deform.cpp b/src/fix_deform.cpp
index 22a4531eec..57bd7eb9cb 100644
--- a/src/fix_deform.cpp
+++ b/src/fix_deform.cpp
@@ -153,6 +153,12 @@ FixDeform::FixDeform(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg)
 
   options(narg-iarg,&arg[iarg]);
 
+  // setup dimflags used by other classes to check for volume-change conflicts
+
+  for (int i = 0; i < 6; i++)
+    if (set[i].style == NONE) dimflag[i] = 0;
+    else dimflag[i] = 1;
+
   // check periodicity
 
   if ((set[0].style && domain->xperiodic == 0) ||
diff --git a/src/fix_deform.h b/src/fix_deform.h
index f34bad600e..201aafd322 100644
--- a/src/fix_deform.h
+++ b/src/fix_deform.h
@@ -20,7 +20,8 @@ namespace LAMMPS_NS {
 
 class FixDeform : public Fix {
  public:
-  int remapflag;
+  int remapflag;                   // whether x,v are remapped across PBC
+  int dimflag[6];                  // which dims are deformed
 
   FixDeform(class LAMMPS *, int, char **);
   ~FixDeform();
diff --git a/src/fix_nph.cpp b/src/fix_nph.cpp
index d3ff39ed12..2fe14a4c44 100644
--- a/src/fix_nph.cpp
+++ b/src/fix_nph.cpp
@@ -24,6 +24,7 @@
 #include "comm.h"
 #include "domain.h"
 #include "modify.h"
+#include "fix_deform.h"
 #include "compute.h"
 #include "kspace.h"
 #include "update.h"
@@ -232,6 +233,14 @@ void FixNPH::init()
   if (atom->mass == NULL)
     error->all("Cannot use fix nph without per-type mass defined");
 
+  for (int i = 0; i < modify->nfix; i++)
+    if (strcmp(modify->fix[i]->style,"deform") == 0) {
+      int *dimflag = ((FixDeform *) modify->fix[i])->dimflag;
+      if ((p_flag[0] && dimflag[0]) || (p_flag[1] && dimflag[1]) || 
+	  (p_flag[2] && dimflag[2]))
+	error->all("Cannot use fix npt and fix deform on same dimension");
+    }
+
   // set temperature and pressure ptrs
   // set ptemperature only if pressure's id_pre[0] is not id_temp
 
diff --git a/src/fix_npt.cpp b/src/fix_npt.cpp
index a0dd52261b..391d957637 100644
--- a/src/fix_npt.cpp
+++ b/src/fix_npt.cpp
@@ -23,6 +23,7 @@
 #include "force.h"
 #include "comm.h"
 #include "modify.h"
+#include "fix_deform.h"
 #include "compute.h"
 #include "kspace.h"
 #include "update.h"
@@ -242,6 +243,14 @@ void FixNPT::init()
   if (atom->mass == NULL)
     error->all("Cannot use fix npt without per-type mass defined");
 
+  for (int i = 0; i < modify->nfix; i++)
+    if (strcmp(modify->fix[i]->style,"deform") == 0) {
+      int *dimflag = ((FixDeform *) modify->fix[i])->dimflag;
+      if ((p_flag[0] && dimflag[0]) || (p_flag[1] && dimflag[1]) || 
+	  (p_flag[2] && dimflag[2]))
+	error->all("Cannot use fix npt and fix deform on same dimension");
+    }
+
   // set temperature and pressure ptrs
   // set ptemperature only if pressure's id_pre[0] is not id_temp