diff --git a/gdl-gsl.patch b/gdl-gsl.patch
new file mode 100644
index 0000000..5d5932b
--- /dev/null
+++ b/gdl-gsl.patch
@@ -0,0 +1,53 @@
+diff -up gdl-0.9.4/src/gsl_matrix.cpp.gsl gdl-0.9.4/src/gsl_matrix.cpp
+--- gdl-0.9.4/src/gsl_matrix.cpp.gsl	2013-09-20 10:10:02.000000000 -0600
++++ gdl-0.9.4/src/gsl_matrix.cpp	2013-09-30 16:57:24.762141411 -0600
+@@ -41,10 +41,11 @@ namespace lib {
+   const int szdbl=sizeof(DDouble);
+   const int szflt=sizeof(DFloat);
+   const int szlng=sizeof(DLong);
++  const int szlng64=sizeof(DLong64);
+ 
+   void ludc_pro( EnvT* e)
+   {
+-    //  cout << szdbl << " " <<szflt << " " << szlng << endl;
++    //  cout << szdbl << " " <<szflt << " " << szlng << " " szlng64 << endl;
+ 
+     SizeT nParam=e->NParam(1);
+     //     if( nParam == 0)
+@@ -120,9 +121,15 @@ namespace lib {
+     dimension dim1(&n, (SizeT) 1);
+     BaseGDL** p1D = &e->GetPar( 1);
+     GDLDelete((*p1D));
+-    *p1D = new DLongGDL(dim1, BaseGDL::NOZERO);
+-    memcpy(&(*(DLongGDL*) *p1D)[0], p->data, 
+-	   p0->Dim(0)*szlng);
++    if (sizeof(size_t) == szlng) {
++      *p1D = new DLongGDL(dim1, BaseGDL::NOZERO);
++      memcpy(&(*(DLongGDL*) *p1D)[0], p->data, 
++	p0->Dim(0)*szlng);
++    } else {
++      *p1D = new DLong64GDL(dim1, BaseGDL::NOZERO);
++      memcpy(&(*(DLong64GDL*) *p1D)[0], p->data, 
++	p0->Dim(0)*szlng64);
++    }
+     
+ //     gsl_matrix_free(mat);
+ //     gsl_permutation_free(p);
+@@ -189,10 +196,15 @@ namespace lib {
+     GDLGuard<gsl_matrix> g1(mat,gsl_matrix_free);
+     memcpy(mat->data, &(*p0D)[0], nEl*szdbl);
+ 
+-    DLongGDL* p1L =e->GetParAs<DLongGDL>(1);
+     gsl_permutation *p = gsl_permutation_alloc (nEl1);
++    if (sizeof(size_t) == szlng) {
++      DLongGDL* p1L =e->GetParAs<DLongGDL>(1);
++      memcpy(p->data, &(*p1L)[0], nEl1*szlng);
++    } else {
++      DLong64GDL* p1L =e->GetParAs<DLong64GDL>(1);
++      memcpy(p->data, &(*p1L)[0], nEl1*szlng64);
++    }
+     GDLGuard<gsl_permutation> g2(p,gsl_permutation_free);
+-    memcpy(p->data, &(*p1L)[0], nEl1*szlng);
+       
+     DDoubleGDL *p2D = e->GetParAs<DDoubleGDL>(2);
+     gsl_vector *b = gsl_vector_alloc(nEl2);
diff --git a/gdl.spec b/gdl.spec
index 86ffd11..3a2142f 100644
--- a/gdl.spec
+++ b/gdl.spec
@@ -25,6 +25,9 @@ Patch4:         gdl-plwidth.patch
 # Fix python build
 # https://sourceforge.net/p/gnudatalanguage/bugs/552/
 Patch5:         gdl-python.patch
+# Fix datatype for use with gsl's permutation type
+# https://sourceforge.net/p/gnudatalanguage/bugs/570/
+Patch6:         gdl-gsl.patch
 Patch13:        gdl-0.9-antlr-cmake.patch
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
@@ -112,6 +115,7 @@ popd
 %patch3 -p1 -b .build
 %patch4 -p1 -b .plwidth
 %patch5 -p1 -b .python
+%patch6 -p1 -b .gsl
 
 %global cmake_opts \\\
    -DWXWIDGETS=ON \\\
@@ -193,6 +197,7 @@ rm -rf $RPM_BUILD_ROOT
 - Update to 0.9.4
 - Update build patch - drop automake components
 - New python patch to fix python build
+- Add patch to fix gsl usage
 
 * Tue Aug 27 2013 Orion Poplawski <orion@cora.nwra.com> - 0.9.3-10.cvs20130804
 - Add patch to support new width() method in plplot