diff --git a/DataTree.cc b/DataTree.cc
index 5c545779..34c97ddb 100644
--- a/DataTree.cc
+++ b/DataTree.cc
@@ -39,6 +39,8 @@ DataTree::DataTree(SymbolTable &symbol_table_arg, NumericalConstants &num_consta
   MinusInfinity = AddUMinus(Infinity);
 
   Pi = AddNumConstant("3.141592653589793");
+
+  steady_state_found = false;
 }
 
 DataTree::~DataTree()
@@ -416,6 +418,7 @@ DataTree::AddNormcdf(NodeID iArg1, NodeID iArg2, NodeID iArg3)
 NodeID
 DataTree::AddSteadyState(NodeID iArg1)
 {
+  steady_state_found = true;
   return AddUnaryOp(oSteadyState, iArg1);
 }
 
diff --git a/DataTree.hh b/DataTree.hh
index 494ee6a9..f9cfd42c 100644
--- a/DataTree.hh
+++ b/DataTree.hh
@@ -64,6 +64,9 @@ protected:
   //! Stores local variables value (maps symbol ID to corresponding node)
   map<int, NodeID> local_variables_table;
 
+  //! true when oSteadyState is encountered in a dynamic model
+  bool steady_state_found;
+
   //! Internal implementation of AddVariable(), without the check on the lag
   VariableNode *AddVariableInternal(int symb_id, int lag);
 
@@ -175,6 +178,8 @@ public:
   //! Checks if a given symbol is used somewhere in the data tree
   bool isSymbolUsed(int symb_id) const;
   //! Thrown when trying to access an unknown variable by deriv_id
+  bool containsSteadyStateOperator() const { return steady_state_found; };
+  //! Thrown when trying to access an unknown variable by deriv_id
   class UnknownDerivIDException
   {
   };
@@ -183,7 +188,7 @@ public:
   virtual int getDerivID(int symb_id, int lag) const throw (UnknownDerivIDException);
   //! Returns the column of the dynamic Jacobian associated to a derivation ID
   virtual int getDynJacobianCol(int deriv_id) const throw (UnknownDerivIDException);
-	
+
   //! Returns bool indicating whether DataTree represents a Dynamic Model (returns true in DynamicModel.hh)
   virtual bool isDynamic() const { return false; };
 };
diff --git a/DynamicModel.cc b/DynamicModel.cc
index 1451f7a9..46b4d585 100644
--- a/DynamicModel.cc
+++ b/DynamicModel.cc
@@ -1129,6 +1129,9 @@ DynamicModel::writeDynamicMFile(const string &dynamic_basename) const
     << "% Warning : this file is generated automatically by Dynare" << endl
     << "%           from model file (.mod)" << endl << endl;
 
+    if (containsSteadyStateOperator())
+      mDynamicModelFile << "global oo_;" << endl << endl;
+
     writeDynamicModel(mDynamicModelFile, false);
 
     mDynamicModelFile.close();