diff --git a/src/output.cpp b/src/output.cpp
index c132ab564b..b7a0c43bbf 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -75,7 +75,8 @@ Output::Output(LAMMPS *lmp) : Pointers(lmp)
   delete [] newarg;
     
   thermo_every = 0;
-
+  var_thermo = NULL;
+  
   ndump = 0;
   max_dump = 0;
   every_dump = NULL;
@@ -98,6 +99,7 @@ Output::Output(LAMMPS *lmp) : Pointers(lmp)
 Output::~Output()
 {
   if (thermo) delete thermo;
+  delete [] var_thermo;
 
   memory->sfree(every_dump);
   memory->sfree(next_dump);
@@ -118,6 +120,15 @@ Output::~Output()
 void Output::init()
 {
   thermo->init();
+  if (thermo_every) delete [] var_thermo;
+  else if (var_thermo) {
+    ivar_thermo = input->variable->find(var_thermo);
+    if (ivar_thermo < 0)
+      error->all("Variable name for thermo every does not exist");
+    if (!input->variable->equalstyle(ivar_thermo))
+      error->all("Variable for thermo every is invalid style");
+  }
+
   for (int i = 0; i < ndump; i++) dump[i]->init();
   for (int i = 0; i < ndump; i++)
     if (every_dump[i] == 0) {
@@ -207,6 +218,11 @@ void Output::setup(int flag)
   if (thermo_every) {
     next_thermo = (ntimestep/thermo_every)*thermo_every + thermo_every;
     next_thermo = MYMIN(next_thermo,update->laststep);
+  } else if (var_thermo) {
+    next_thermo = static_cast<int> 
+      (input->variable->compute_equal(ivar_thermo));
+    if (next_thermo <= ntimestep)
+      error->all("Thermo every variable returned a bad timestep");
   } else next_thermo = update->laststep;
 
   modify->addstep_compute(next_thermo);
@@ -279,7 +295,13 @@ void Output::write(int ntimestep)
     modify->clearstep_compute();
     thermo->compute(1);
     last_thermo = ntimestep;
-    next_thermo += thermo_every;
+    if (thermo_every) next_thermo += thermo_every;
+    else {
+      next_thermo = static_cast<int> 
+	(input->variable->compute_equal(ivar_thermo));
+      if (next_thermo <= ntimestep)
+	error->all("Thermo every variable returned a bad timestep");
+    }
     next_thermo = MYMIN(next_thermo,update->laststep);
     modify->addstep_compute(next_thermo);
   }
diff --git a/src/output.h b/src/output.h
index 22b821af95..12668c2cfc 100644
--- a/src/output.h
+++ b/src/output.h
@@ -25,6 +25,8 @@ class Output : protected Pointers {
   int next_thermo;             // next timestep for thermo output
   int thermo_every;            // thermo output every this many steps
   int last_thermo;             // last timestep thermo was output
+  char *var_thermo;            // variable name for thermo frequency
+  int ivar_thermo;             // variable index for thermo frequency
   class Thermo *thermo;        // Thermodynamic computations
 
   int ndump;                   // # of Dumps defined
diff --git a/src/thermo.cpp b/src/thermo.cpp
index 77dd495f95..6d36469f84 100644
--- a/src/thermo.cpp
+++ b/src/thermo.cpp
@@ -376,7 +376,18 @@ void Thermo::modify_params(int narg, char **arg)
 
   int iarg = 0;
   while (iarg < narg) {
-    if (strcmp(arg[iarg],"temp") == 0) {
+    if (strcmp(arg[iarg],"every") == 0) {
+      if (iarg+2 > narg) error->all("Illegal thermo_modify command");
+      if (strstr(arg[iarg+1],"v_") == arg[iarg+1]) {
+	delete [] output->var_thermo;
+	int n = strlen(&arg[iarg+1][2]) + 1;
+	output->var_thermo = new char[n];
+	strcpy(output->var_thermo,&arg[iarg+1][2]);
+	n = 0;
+      } else error->all("Illegal thermo_modify command");
+      output->thermo_every = 0;
+      iarg += 2;
+    } else if (strcmp(arg[iarg],"temp") == 0) {
       if (iarg+2 > narg) error->all("Illegal thermo_modify command");
       if (index_temp < 0) error->all("Thermo style does not use temp");
       delete [] id_compute[index_temp];