diff --git a/DynamicModel.cc b/DynamicModel.cc
index 4df16e6c..6e4e3ed5 100644
--- a/DynamicModel.cc
+++ b/DynamicModel.cc
@@ -1904,7 +1904,7 @@ DynamicModel::writeOutput(ostream &output, const string &basename, bool block_de
 
   // Write equation tags
   output << "M_.equations_tags = {" << endl;
-  for (unsigned int i = 0; i < equation_tags.size(); i++)
+  for (size_t i = 0; i < equation_tags.size(); i++)
     output << "  " << equation_tags[i].first + 1 << " , '"
            << equation_tags[i].second.first << "' , '"
            << equation_tags[i].second.second << "' ;" << endl;
diff --git a/ParsingDriver.cc b/ParsingDriver.cc
index b7abea8a..38f08a1e 100644
--- a/ParsingDriver.cc
+++ b/ParsingDriver.cc
@@ -493,7 +493,7 @@ ParsingDriver::add_det_shock(string *var, bool conditional_forecast)
 
   vector<ShocksStatement::DetShockElement> v;
 
-  for (unsigned int i = 0; i < det_shocks_periods.size(); i++)
+  for (size_t i = 0; i < det_shocks_periods.size(); i++)
     {
       ShocksStatement::DetShockElement dse;
       dse.period1 = det_shocks_periods[i].first;
diff --git a/Shocks.cc b/Shocks.cc
index 0fd26ea3..da3981e3 100644
--- a/Shocks.cc
+++ b/Shocks.cc
@@ -46,7 +46,7 @@ AbstractShocksStatement::writeDetShocks(ostream &output) const
       bool exo_det = (symbol_table.getType(it->first) == eExogenousDet);
       int set_shocks_index = ((int) mshocks) + 2 * ((int) exo_det);
 
-      for (unsigned int i = 0; i < it->second.size(); i++)
+      for (size_t i = 0; i < it->second.size(); i++)
         {
           const int &period1 = it->second[i].period1;
           const int &period2 = it->second[i].period2;
diff --git a/SigmaeInitialization.cc b/SigmaeInitialization.cc
index 6228e46c..4d3d4e71 100644
--- a/SigmaeInitialization.cc
+++ b/SigmaeInitialization.cc
@@ -28,7 +28,7 @@ SigmaeStatement::SigmaeStatement(const matrix_type &matrix_arg) throw (MatrixFor
 SigmaeStatement::matrix_form_type
 SigmaeStatement::determineMatrixForm(const matrix_type &matrix) throw (MatrixFormException)
 {
-  unsigned int nbe;
+  size_t nbe;
   int inc;
   matrix_form_type type;
   // Checking if first or last row has one element.
@@ -61,8 +61,7 @@ SigmaeStatement::determineMatrixForm(const matrix_type &matrix) throw (MatrixFor
 void
 SigmaeStatement::writeOutput(ostream &output, const string &basename) const
 {
-  unsigned int ic, ic1;
-  unsigned int ir, ir1;
+  size_t ic, ic1, ir, ir1;
 
   output << "M_.Sigma_e = [..." << endl;
   for (ir = 0; ir < matrix.size(); ir++)